Wednesday, 22 November 2017

Apple Power Macintosh G5: Flame On

Let's have a look at the Apple Power Macintosh G5, a weighty space heater that can also perform computing tasks. So weighty that it creases my paper backdrop, even if I put something underneath it. Apple launched the G5 in 2003 with great fanfare, but nowadays it has a decidedly mixed legacy. In 2003 it was a desktop supercomputer that was supposed to form the basis of Apple's product range for years to come, but within three years it had been discontinued, along with the entire PowerPC range, in favour of a completely new computing architecture. The G5 puts me in mind of an ageing footballer who finally has a chance to play a World Cup match; he is called up from the substitute's bench, entertains the crowd for twenty minutes, but the team loses, and by the time of the next World Cup the uniform is the same but the players are all different. Our time in the sun is brief, the G5's time especially so.

I've long been a PC person, and from my point of view the G5 came and went in the blink of an eye. I knew that it had a striking case and a reputation for high power consumption and heat output, and for being 64-bit at a time when that was rare in the PC world, but that's about it. Almost fifteen years later G5s are available on the used market for almost nothing - postage is incredibly awkward - so I decided to try one out. Mine is a 2.0ghz dual-processor model, the flagship of the first wave of G5s. Back in 2003 this very machine was, in Apple's words, "the world's fastest, most powerful personal computer".

Before turning it on for the first time I informed the local flying club that I was about to activate a powerful radio frequency source. I sent a letter to the Home Office and British Telecom and my electricity provider to inform them that I was not a terrorist, and that the souls of the dead are reincarnated on Jupiter, and that I no longer wished to be married to Helena Bonham-Carter. Furthermore I removed all of my clothes out of fear and assumed a defensive posture, attempting to prove to any and all observers that I was no harm to anyone.

I was slightly disappointed when the machine started not with flames but with a muted whoosh, which settled down into a quiet hum. Nothing exploded or shuddered. Masked men did not burst into the room. Instead there was a familiar chime and OS X 10.5.8 loaded up.

My G5 still had its original 160gb 7200rpm hard drive, which was very noisy. The date code says that it was constructed in August 2003.

I have a gadget that can measure the power consumption of electrical items. My desktop PC is a quad-core 64-bit i5-2500k running at 3.3ghz, with an SSD, two spinning hard drives, and an Nvidia GTX 750. I built it back in 2011, and apart from adding the graphics card and SSD I haven't felt the need for more power.

According to my gadget the PC idles at 70 watts and at full whack consumes 150 watts of power. Under load that's about the same as a modern 4K television, perhaps slightly more if I include the PC's monitor, but my PC rarely runs at full power.

The G5 plays DVDs perfectly well, like every desktop computer since the late 1990s. The G5 predated Blu-Ray, but there were a couple of G5-compatible Blu-Ray drives. They were only useful for burning data discs, however, as only the fastest G5s had the necessary combination of processor grunt and graphics hardware to decode Blu-Ray video, and even then finding PowerPC software that would play Blu-Ray films was problematic.

In comparison my new, fourteen-year-old Power Macintosh G5 has two separate 64-bit PowerPC 970 processors running at 2ghz. It has two spinning hard drives and an ancient Radeon 9600. At idle it consumes 140 watts of power - only ten watts less than my PC under load - and when taxed it sucks up 280+ watts. That's almost twice as much as my fridge, and apparently with very heavy processing power consumption goes up to 400+ watts. On the positive side the G5 is quieter than my PC. It has more fans, but they run slower, only going mad every once in a while.

OSX 10.5.8 Leopard was the final version of OSX for the PowerPC-era Macintoshes. Leopard is now ten years old. It's a close contemporary of Windows Vista, but whereas Vista was mocked as a bloated mess Leopard was generally regarded as a decent-albeit-inessential upgrade of 10.4 Tiger. As a PC person I'm impressed with how well Leopard and the G5 have aged. The toned-down look of mid-decade OSX Leopard is still attractive. It recognises USB peripherals without popping open an irritating dialogue box, the interface feels smoother and less flaky than Windows XP on a similarly old machine, and the tablet-esque "cover flow" feature feels ahead of its time.

Cover Flow was included in the first iPhone, released at almost the same time as Leopard in 2007, and although Apple has subsequently fallen out of love with Cover Flow it remains part of MacOS nowadays. Leopard runs an obsolete version of iTunes, version 10, which is faster and easier to use than the latest version.

Back in 2005 there was some debate as to whether Tiger (older, less featuresome, but faster) or Leopard (a few more features, more modern, slower) was the best choice for the Power Macintosh G5. I'm in two minds. My hunch is that the minor performance hit of Leopard is insignificant on the faster G5s, but on the other hand very little OSX software was made obsolete in the jump from 10.4 to 10.5 - Photoshop CS4 and Logic Pro 8 also work on 10.4 - so beyond a feeling of completeness there's no pressing practical need to switch from 10.4 to 10.5.

A pair of 1TB Western Digital Caviar Greens I had lying about. with jumpers over pins 5+6 to force them into SATA-I/II mode. The Intel-powered Macintosh Pro had four drive bays arranged from front to back through the middle of the machine, with "cold swappable" caddies. The G5 isn't quite as elegant - the caddy is fixed in place, and the drives go on backwards, so you still have to plug in the SATA connectors. G5-era OSX had software RAID support, although I suspect an SSD would be more sensible.

I bought the G5 mainly to use Logic Express, a music sequencer. Here's a song I wrote with this combination, as featured in the previous post:

And here's a little video of Logic Express performing the track. A more complex arrangement with masses of reverb would sorely tax the CPU, although it wouldn't be too hard to fix this with creative bouncing:

There was something melancholic about the process of setting up Logic Express. Logic's big selling point is its simple interface and its massive selection of genuinely good built-in sound generators, in particular a decent software sampler that has a range of usable, natural-sounding, but not annoyingly obvious instruments. Logic uses AU "audio unit" plugins instead of the more common VST standard. There was a boom time in the early 2000s when masses of free VST/AU plugins were available, but over the years the market has died off, partially because the audio units included with the modern Logic Pro X are extensive and well-made, partially because the developers have moved on.

So there was something sad about hunting down old plugins that were last updated in 2007, hosted on personal websites that died in 2011, or that remain as shells with (c) 2005 dates on them. It's as if creative electronic computer-based music flourished in the early part of the 2000s and then died suddenly, which is surely not the case, but browsing through dead links gives that impression. HyperUPIC and Sonasphere, for example, appear to have completely left the internet, never to return. Fortunately MDA and DestroyFX still exist. Perhaps I'm out of touch.

ZDoom works fine with the G5. As far as I can tell there are no 3D-accelerated PowerPC Doom ports, although the G5's hardware would be more than capable of running them. By coincidence the last high-profile PowerPC game was Id Software's Doom 3, but I don't have a copy so I can't check it out.

The only PowerPC browser actively maintained today is TenFourFox, which is based on FireFox. On my 1.67ghz PowerBook G4 it's painfully slow, but it's much more usable on a G5. It even accesses the web version of Google Drive without grinding to a halt. It has very limited support for online high-def video and Netflix is a distant dream, but on the whole it makes the G5 almost a usable everyday machine, especially if you own a solar power plant. I imagine the late dual-core and quad-core G5s would be pretty speedy.

The problem of course is that the same could be said of almost any cheap laptop or Windows tablet released during the last ten years, minus the bit about having a solar power plant. The laptop would probably have more USB ports, and might well have USB 3, which would compensate for the G5's second drive bay. Anandtech made this very point when they tested one of the later G5s against a 2010 Mac Mini, which was generally faster while using roughly one-tenth the power. My late-2008 MacBook Pro, for example, is slightly less flexible than the G5 but runs MacOS High Sierra and is much faster.

Fourteen years later the exterior of the case is still stunning. The interior has however tarnished a bit.

I decided to benchmark my G5. I ran the trial version of Geekbench 2, an older benchmarking utility that runs on different platforms. Geekbench is as old as the G5, and in a neat coincidence it uses the lowest-specification Power Macintosh G5 as its benchmark, with a score of 1000. Perhaps the author wrote the original version on a G5. I don't know.

My 2.0ghz dual-processor G5 scores 1645, which makes it 60% faster than the 1.6ghz entry-level model, or at least the benchmark score is 60% higher. That's reasonable given that the 1.6ghz model had a lower clock speed, slower memory, a lower bus speed and only one processor.

The G5 again. It was divided into three thermal zones. The front of the machine is to the left. From top to bottom, left to right, the top compartment has a DVD drive, a pair of fans, and two hard drives. The middle compartment has a fan plus mono speaker mounted in front of a 56K modem, followed by space for PCI-X cards and the AGP graphics card. At the rear of the machine is a catch that releases the access panel.
The lower compartment has the memory sitting beneath a Wi-Fi/Bluetooth card, then the CPU modules and their heatsinks, then another pair of fans. The base of the case contains a hefty 600w power supply.

The 17" 1.67ghz PowerBook G4 I wrote about last month scores 883, drawing just 47 watts whilst doing so, which suggests that the 1.6ghz Power Macintosh G5 wasn't much cop. Putting it another way, my G5 draws six times more power than a contemporary G4 laptop, but benchmarks only twice as fast. I realise I'm comparing two different fruit, but the G5 feels like an attempt to achieve performance gains with brute force rather than sophistication. It also feels like the result of two companies with different product release schedules trying to reach an uneasy compromise. The G5's deficiencies were masked by the fact that contemporary PCs were just as power-hungry, but therein lies a history lesson.

In the 1980s and 1990s home computers didn't use much electricity. No-one cared about "thermal design power" and most computers were either air-cooled or used a single fan to push air over the power supply unit. By the 2000s however heat became a major issue. Intel's Pentium 4, introduced in 2000, was a small step in terms of performance improvements over the Pentium III but a giant leap in heat output. Even without overclocking the typical Pentium 4 system required a PSU fan, a CPU fan, a case output fan, perhaps input fans and a fan on the graphics card. I call the early-mid 2000s the time of nine fans.

Eventually the Pentium 4's design team reached something called the "power wall", whereby the gains from extra clock speed were outweighed by the difficulty of cooling the chip. Furthermore a phenomenon called electromigration, whereby circuitry degrades at higher temperatures, started to eat into the lifespan of the chips. This is one of the reasons why modern CPUs tend to use multiple, modestly-clocked cores rather than one single very fast processing unit.

The Power Macintosh G5 did actually have nine fans. My Power Macintosh G5 has nine fans. Two are hidden away in the base of the machine, where they are attached to the power supply unit. Four fans front and back draw air over the gigantic CPU heatsinks. There's a single fan in the middle, which airs the PCI cards, and two small fans blow air over the hard drives and rear of the motherboard.

That's nine fans. I've counted. Two plus four (six) plus one (seven) plus two (nine) equals nine. The case has an array of temperature sensors that make sure everything is cooled effectively. Each machine apparently has a unique thermal profile stored somewhere in its BIOS. Some modifications require that the thermal profile is recalibrated before the fans work properly again, and you can only do that with Apple's G5 diagnostic tools, which aren't publicly available.

Photoshop CS2 - technically Bridge - plus TenFourFox. In this shot I've had to use Adobe's DNG converter to convert my camera's RAW files. Good luck finding the last version of Adobe's DNG converter that supports the PowerPC! The G5 will run up to CS4, which is still competent nowadays.

The G5's case is a clever piece of design that works well, but there must have been a better way. Imagine if the time and brainpower spent dealing with the G5's heat generation had been applied to other problems instead. Back in the 1990s the PowerPC chip was touted as an efficient, RISC-based alternative to the Intel 80X86. It ran at lower clock speeds than contemporary Pentiums but did as much work. Successive generations of the PowerPC chip kept Apple Macintoshes competitive during the late 1990s, but the architecture started to lag in the early 2000s with the introduction of second-generation Pentium 4s and efficient X86 clones from AMD. The G3 and G4 remained competitive mobile chips but Apple was in danger of having its desktop machines fall behind.

The PowerPC G5, formally known as the IBM PowerPC 970, was Apple's great white hope. It was announced at Apple's 2003 keynote presentation, which is available on Youtube:

The keynote is like something from a parallel world. Nowadays Apple's product announcements are full of 3D face recognition and all-glass backing and dual-lens cameras and rose gold; in 2003 the company chose to highlight the G5's bandwidth and bus speed and its advanced chip fabrication technology. Nowadays Apple doesn't talk about cost - if Sir or Madam baulks at the price of a new MacBook Pro, perhaps Sir or Madam might consider going elsewhere - but in 2003 the G5 was sold as a cheaper alternative to an equivalent dual-Xeon PC. There was also a rackmounted file server version of the G5, the XServe, which is something the modern Apple would never dream of releasing. This was a time when Apple was fond of pointing out the UNIX roots of OS X.

On paper the G5 looked terrific. The PowerPC 970 was a 64-bit chip attached to a system bus that ran at lighting speed, with a multi-processor-enabled architecture that could access up to 8gb of memory, with SATA hard drives and an awesome case. All except the most basic Power Macintosh G5 machines had either two CPUs or a dual-core chip - in one case two dual-core chips - and later machines increased the memory limit to 16gb, with the last batch of G5's adding support for PCI-e. Even in 2017 the idea of a quad-core desktop PC with 16gb of memory plus SATA and PCI-e sounds current.

The G5's considerable weight is focused on these little pads. There were aftermarket cork pads, but I've used masking tape to wrap a pair of old cycle gloves around the handle-stands, which doesn't change the fact that in 1998 The Undertaker threw Mankind off Hell In A Cell, causing him to plummet sixteen feet through an announcer’s table.

As mentioned earlier Apple's television adverts claimed that the G5 was "the world's fastest, most powerful personal computer", although here in the United Kingdom the ITC objected to that claim and forbade Apple from repeating the ad. The single-processor machines weren't particularly impressive, but the G5 was new and hopefully had room for expansion whereas the Pentium 4 and Xeon were in 2003 several years old.

But that seems to be where things went wrong, because the G5 didn't have room for expansion. Or contraction, because no matter how hard IBM tried they couldn't produce a chip that would fit into a laptop. The PowerPC 970 was simply too power-hungry, and when underclocked it didn't run much faster than the G4, and the 64-bit architecture was of questionable benefit in a mobile context. Many years later ARM demonstrated that it was possible to make incredibly frugal, powerful mobile RISC chips, but that was still science fiction in the early 2000s.

The G5's 64-bit architecture was something of a false start. Only a handful of applications used the G5's 64-bit address space, and although OSX could access huge amounts of memory it didn't have a 64-bit kernel for several years. When Apple abandoned the PowerPC they temporarily took a step back into a predominantly 32-bit world with the Core Duo, only fully embracing 64 bits a few years later, with the Core 2 Duo and OS X 10.7.

Logic Express is essentially a multi-track audio / MIDI sequencer on a G4 PowerBook. On a G5 however it will run lots of instruments and effects at once.

The G5's lack of mobile mojo was unfortunate in a world that was gradually pivoting towards mobile computing and mobile internet, doubly so given that half of Apple's profits came from its laptops. It's fascinating to speculate whether IBM's inability to make a mobile G5 was a result of its inability to do so or from a lack of motivation. In the past IBM had made mobile versions of the 80386, and it had even sold RISC-powered versions of the ThinkPad laptop, but that was a long time ago, and IBM had no other use for mobile chips. In the early 2000s Apple had turned the corner into profitability but from IBM's point of view Apple was still just another customer, of relatively minor importance. IBM might have spent a fortune setting up a dedicated POWER mobile team, but to what end?

And there was something else. Intel had launched the Pentium 4 with great hopes that it would still be around in ten years, but development hit a brick wall in the early 2000s, and for a brief period AMD seemed poised to become the dominant player in the X86 market. Intel's problems with the hot, power-hungry Pentium 4 mirrored those of IBM with the G5, but whereas IBM was uninterested in a mobile G5 Intel made three concerted attempts to stuff the Pentium 4 into laptops, failing each time. To its credit Intel wasn't too proud to admit defeat. After going back to the drawing board the company came up with the Pentium M, which was released to the world in 2003, just as Apple was putting the finishing touches on the Power Macintosh G5.

The Pentium M was perhaps the most influential CPU of the early 2000s. Very few people recognised it at the time. With the exception of a few small-form-factor PCs it was generally fitted into laptops, which were of limited interest to performance enthusiasts. Laptops had a reputation for being underpowered; no-one in 2003 expected that the Pentium M would be any good. Its name was easy to confuse with the earlier Pentium 4M, and furthermore Intel insisted on downplaying the Pentium M in favour of the Centrino platform. Part of this unwillingness to publicise the Pentium M might have come from the fact that the design owed more to the Pentium III than the Pentium 4. I imagine Intel was unwilling to make the Pentium 4 look bad given that it was still theoretically their desktop flagship.

But not for long. The Pentium M didn't just outperform the Pentium 4M mobile chip, it also benchmarked within a few percent of the desktop Pentium 4, while consuming less power and generating less heat. After a brief diversion with the Pentium D Intel essentially gave up on the Pentium 4 in favour of a multi-core development of the Pentium M, which was sold as the Core architecture. The mostly-mobile Core Duo and desktop-oriented, 64-bit Core 2 Duo went on to re-establish Intel's dominant position in the X86 marketplace.

Apple had, as a side project, already ported OSX to the X86 architecture. There were rumours that Pentium 4-based development machines actually ran OSX faster than the G5. At some point Apple's engineers must have become privy to the Pentium M development roadmap, and in mid-2005 Apple publicly announced that it was saying goodbye to the PowerPC architecture in favour of Intel.

Given the G5's notorious heat issues the switch to Intel was less of a shock that it might have been. I have the impression that long-term Apple fans are fond of the PowerPC era and nostalgic for the likes of the dual-processor, mirrored drive door G4, but not blind to the G5's faults. Apple fans aren't like Amiga fans, thank goodness. They know when to admit defeat.

The fans pull straight out. Further work generally isn't necessary - it's easy enough to blow dust out of the heatsinks, and the airflow tends to keep the G5's interior surprisingly clean. Most other faults are terminal and can be fixed by throwing the G5 into a deep bog and buying a new one instead. The single-processor models just had the top heatsink and fan. The liquid-cooled models enclosed the CPUs and cooling unit in a single large block.

The Pentium M's life ran alongside the PowerPC 970/FX used in the G5. They were both launched in 2003 and ended their lives in 2005. During that period the Pentium M underwent a die shrink and scaled from 1.3ghz up to 2.27ghz, roughly doubling in performance in the process. The PowerPC 970 also underwent a die shrink, but its performance increases were more modest until the very last wave of multi-core G5s, which were impressively fast but not enough to change Apple's mind.

The first wave of G5s consisted of a 1.6ghz entry-level model, a 1.8ghz also entry-level model, and a 2ghz dual-processor flagship. The second wave, launched in mid-2004, introduced the more efficient 970FX processor but was otherwise very similar to the first wave, with a 2.5ghz model sitting at the top of the range. Performance-wise the second wave seemed to be only slightly faster than the first. A third wave came out in mid-2005, but again the machines were much the same as their predecessors. The last batch of G5s emerged in October 2005 and introduced dual-core processors and PCI Express ports. They were launched when it was already known that Apple was going to abandon PowerPC and were therefore doomed to be the last of the line.

Apple also launched a couple of orphan G5s - a 1.8ghz Dual Processor machine that filled out the bottom of the range, and a single-processor 1.8ghz model that used iMac components in an attempt to sell a budget model. More than half of the fourteen different G5 models ran at 1.8ghz or 2.0ghz. The final, dual-core 2ghz model was only slightly faster than my first-generation 2ghz dual-processor G5; the last 1.8ghz model was actually slower than its predecessors. Meanwhile the later high-end models needed liquid cooling units to tame their incredible thermal output.

Within a few years some of the liquid cooling units developed leaks that could silently corrode the machines away from the inside. Some units were more reliable than others, but nonetheless the effect on the resale value of liquid cooled G5s was dramatic. If you don't want to bother with liquid cooling the most powerful non-liquid G5s are the third-wave dual-processor 2.3ghz models and the 2005 dual-core 2.0ghz and 2.3ghz models, of which the dual-core models are the most desirable due to the inclusion of PCI-express.

The access panel is a rigid, weighty chunk of aluminium. If the entire G5 run had fallen through a timewarp to Nazi Germany circa 1941 the scrap aluminium could have filled the sky with Messerschmidts.

Upgrading the G5 is generally easy. In ascending order of difficulty, easy first:

All but the most basic models had eight RAM slots, which accept memory in pairs, working from the inside out. They aren't picky; you can mix brands and capacities. My G5 has the two 256mb sticks it was sold with, plus a pair of 512mb sticks, plus two pairs of 1gb sticks for a total of 5.5gb. The later models could accept up to 16gb of memory, although from what I have read advances beyond 4gb in Leopard give only minimal improvement and only then if you're using something like Photoshop a lot. The memory is air-cooled and does tend to get hot. My desktop PC has four slots but two of them are blocked by hard drive cables; the G5's memory is easy to reach.

All models take SATA hard drives, but the early models were designed for the SATA-I standard. This means that if you use a modern SATA-III drive, you have to put a little jumper over pins 5-6 to enable SATA-I/II compatibility. I have a packet of these little jumpers. I'll paste some of them into the next line so that you can use them:

The G5 is fussy with SSDs, and OS X 10.5 doesn't support TRIM, and even though SSDs are now trivially cheap I had a pair of old Western Digital Caviar Green HDDs sitting about doing nothing, so I used them instead. I cloned the operating system across. My original G5 hard drive is in theory faster than the Caviar Green (7200rpm vs 5400rpm), but it was very noisy, and in my personal experience new slow drives tend to be better performers than old fast drives.

The G5 uses PCI-X slots, which are compatible with original PCI cards. PCI-X was a dead-end standard common in servers; it was obliterated by PCI-Express. In 2017 you will only find PCI-X cards on the used market. My G5 came with a four-port eSATA PCI-X card that will connect with external eSATA hard drives and a Mark of the Unicorn audio interface card that's useless without an external hardware module that I don't have. Most PCI-X cards were for storage, ethernet access, RAID controllers and the like. Sadly there don't seem to be any PCI-X USB cards.

eSATA, by the way, was essentially SATA but for external drives. As with FireWire 800 it was competitive with USB for a while but eventually overshadowed by USB 3.0. eSATA doesn't transfer power, so you can only use drives and drive arrays that have their own power supplies.

The G5 has three USB 2 ports, two FireWire 400 ports, and a FireWire 800 port. In my life I have never used FireWire to transfer data. I will probably go to my grave having never used FireWire.

The initial wave of G5s shipped with graphics cards that had a DVI port and an ADC port. What was ADC? It was a proprietary Apple thing that, like so many proprietary Apple things, was technically clever enough that it didn't seem like deliberate lock-in, but nonetheless didn't even take off within the Apple ecosystem, let alone outside it. Only a handful of Apple monitors supported it and the standard was essentially dead even before the G5 came out. There are ADC-DVI adapters available, but they're too expensive to make sense. The later G5s used graphics cards with dual DVI outputs; the most powerful had a dual-link DVI port that could drive the 30", 2560x1600 Apple Cinema Display.

Early G5s used AGP; later models used PCI-E. My G5 has an air-cooled Radeon 9600. In theory I could upgrade the card, but in practice the G5 only accepts Macintosh-only versions of the various graphics cards that were available, and they're rare on the used market because most of them were sold with the G5 rather than separately. There's not much point upgrading the G5's graphics card unless you want to use dual monitors. OS X might feel slightly snappier. The few games available for the G5 might run faster. I would be wary of the extra heat and power draw.

Everything Else
My G5's optical drive is a bit flaky. Sometimes it reads a disc, sometimes it doesn't. Replacing it is apparently easy but I'm not going to bother. There was a brief period in the early 2000s when it was feasible to back up data to a writeable DVD but with the availability of cheap SD cards and USB sticks there's no point any more.

Fans, brackets, antennae and other components are still widely available. The G5 is in theory entirely replaceable - you can build a new one from spare parts and an empty case, if you have a copy of Apple's thermal calibration software - but there's no point when so many G5s are available on the used market.

As a long-term ownership proposition the G5 is problematic. The fastest models were outpaced by their Intel replacements either immediately or within a couple of years, and are thoroughly obsolete nowadays; the G5's power consumption is a reminder of a time when oil was cheap, interest-only mortgages were a fantastic idea, and the economy was not only going well, it would continue to go well forever. Using the G5 as a file server or overnight rendering machine is an expensive proposition. As a space heater it's less efficient than an actual space heater unless you do useful work with it.

On a more esoteric level the G5's fantastic case can be stripped out and used to house a PC, although it's tricky because the ports and buttons don't conform to the PC standard. This chap here chopped his down and made a cute G5-based mini-PC. Alternatively you could gaffer tape a Mac Mini to the inside and just run all the cables through the cooling holes, using a little stick to press the power button. Two G5s joined with a plank of wood make a neat coffee table. Turned on its side, stacked, and suitability modified the G5 can be used as a chest of drawers. The G5's metal case generally resists corrosion but isn't stainless, so its marine applications are limited.

Seriously though, the G5's aluminium case is now both its greatest strength and its greatest weakness. On the downside it's too huge to send through the post, but on the upside it's a solid, genuinely impressive work of engineering that feels useful as a spare part, if only as an object d'art. Apple is routinely mocked for putting style ahead of substance, but the G5's case is a superb example of a functional design that works well and is also beautiful to look at and indeed think about.

Even with the fan in place there's still a large empty space in front of the memory chips. Enterprising storage vendors sold brackets that could house extra hard drives in this space, although bearing in mind that the memory chips get hot I'm sceptical that it would have been a good idea. I often wonder if Apple could have sold a scaled-down G5 case purely as a robust RAID enclosure, with fans etc.

Back to Geekbench. My 2003 2.0ghz dual-processor G5 scores 1645 while consuming 280+ watts of power. In comparison my late-2008 unibody MacBook Pro laptop, powered by a 2.4ghz Intel Core 2 Duo, scores 2758, drawing 45 watts in the process. By that time the Intel-powered, eight-core Macintosh Pro was Geekbenching values of almost 10,000. My desktop PC, an Intel i5-2500k, Geekbenches at 8238, consuming 150 watts. One criticism levelled at the Intel-powered Macintosh Pro was that despite its class-leading power, the edge it had over ordinary Core 2 Duo / i5-powered Intel hardware didn't justify the cost, but that's another argument for another blog post.

Judging by Everymac's figures the very last, quad-core G5 Geekbenched at 3316, which is very impressive for a machine now twelve years old. I imagine it would still have a niche in a recording studio, if you had the aforementioned MOTU audio interface and the appropriate version of Logic Pro and were so familiar with the workflow that it would be disruptive to change. I shudder to think of that setup's power consumption over twelve years of use.

What's the logical next step from a G5? That's a difficult question. Apple intended for you to replace your G5 with an Intel-powered Mac Pro. The Mac Pro used the same basic case design as the G5, albeit that the interior was rejigged. It was conceptually much the same as the G5, combining multiple processors and multiple drive bays with a plethora of RAM slots and ports. However the switch to Intel coincided with a new appreciation for frugal computing, and many former G5 owners opted for one or more Mac Minis instead, using USB and latterly Thunderbolt for external storage.

The G5-descended Macintosh Pro was discontinued in 2013. Apple then intended for professional users to adopt the next-generation Mac Pro, a tubular monstrosity that defies description, but in practice professionals often switched to 5K iMac, assuming they remained with the Macintosh platform at all.

The problem is that the basic design philosophy of the G5 and Mac Pro - monster processors, tonnes of internal storage, all in a big case - is a throwback to the past, because for all but edge cases standard desktop processors are fast enough and faster ports mean that external storage isn't appreciably slower than internal storage any more. Furthermore The Cloud continually eats away at the idea of a fat client of any kind.

From top to bottom the graphics card has DVI and ADC ports. Then there are holes for the wi-fi and Bluetooth antennae, although my machine connects to the internet without them. Then SPDIF, line out, line in, USB 2, Firewire 400, Firewire 800, Ethernet, Modem. The small front panel has the power button, a headphone port, USB 2, Firewire 400. I've plugged in a USB hub, because three USB ports isn't enough.

Nowadays the G5 is a magnificent example of excess. The Wild Bunch of Sam Pekinpah's classic Western "came too late and stayed too long"; the G5 came too late, but with a lifespan of only three years its time was brief.

And gone forever, because fifteen years later the public's appetite for electricity-guzzling computers is about as great as that for petrol-guzzling cars, e.g. nil. Some G5s probably soldier on in recording studios, and if you happen to be given one for free and you're willing to leave the television turned off and never use the oven it's a perfectly usable albeit very slow desktop computer. It's the cheapest Macintosh desktop tower that's still generally usable.

But even a cheap Intel Atom-powered Windows tablet outperforms it, and once you get bored you face the difficult prospect of selling it on again. If you live near a small airfield they might be able to use it as means of de-icing aeroplanes. When I tire of mine I will offer it to the Royal Navy as a potential replacement for their amphibious assault craft. On the one hand aluminium has a tendency to melt at high temperatures, but on the other hand the RN is strapped for cash, besides which ships have access to huge amounts of seawater, the end.

EDIT: After writing the above I decided to see if I could get Linux working. Until a few years ago Linux generally had PowerPC support, although this was more theoretical than actual - several distributions claimed to support the PowerPC architecture, but very few people seemed to have got it working. Debian was the easiest so I tried Debian. I didn't bother with dual-booting; I just popped in a spare hard drive and installed on to that, thus swapping the UNIX-based OS X for a home-made UNIX clone. Unfortunately it wasn't much cop.

Firefox on Debian on a Power Macintosh G5 in 2017, failing to load a page. It just stops.

I used Debian 8, because PowerPC support was dropped from Debian 9. After some messing around with partitioning and then installing the appropriate firmware for Airport Express I had a working computer with wi-fi, but it was surprisingly slow and clunky for a dual-processor Pentium 4-class machine with seven gigabytes of memory. Perhaps it wasn't using the graphics card properly. In comparison OS X sped along.

Debian on the PowerPC has a modern version of Firefox, albeit not the most modern version, which was unusably slow and didn't render pages fully. Most other browsers either crashed immediately - perhaps Java was the problem - or were only a step removed from text-mode browsing. Could I have fixed this by spending my precious time reading five-year-old forum posts and typing strings of arcane characters in a terminal window? I don't care. There's no point. "Software sells hardware", as the saying goes. I bought a MacBook Pro with my own money purely to use Logic; I have an Android mobile phone because it runs OSMAnd. I couldn't care less about Debian because it has nothing I want, so into the bin it goes.