This Swedish forum post has a good description of the innards (translation stolen from a Mac site):
Today 99mac got the chance to look more closely at the G5 and to take some photos to allow our readers to build up their understanding of the new model.
Apple Sweden and MacSupport (I'm guessing at this bit - I've no idea what "trixade" means - any Swedes here?) did their thing and wangled us a machine to test. The machine we test drove was the top model with twin 2GHz G5s and 2GB of RAM.
The G5 is significantly bigger than previous models, being a full 20 inches (50cm) high which happens to make it an inch too big for a standard 19" rack. Perhaps it's so that users will want to stick to Xserves screwed in place in a server environment - earlier it was possible to buy small rack adapters to screw the G4s in a rack.
The G5 gives a more competent and industrial impression than the soft, plasticky G4. The chassis is of one piece of aluminium and has a combination of soft flowing lines and sharp edges. The quality of the details is fascinating and I'd go so far as to say that no other computer has been so well built or designed to this level of detail. This is the computer world's Global or Porsche.
When opening the chassis we're met by a large windshield of plexiglass or transparent plastic. The shield is there to direct streams of cold air through the computer. A total of nine fans apparently sit within the computer but we found only eight during our time with the machine. Without the shield the computer won't start, perhaps because it might burn up without the right amount of cold air. It does however work perfectly without the side panel - a way to impress other computer users (shades here of the Ferrari 360 Modena which has the motor cover made of glass).
On the inside it's the two G5 processors and their enormous heatsinks which dominate. There's no doubt as to where the processors sit. A really large motherboard is quite sparsely populated and covers the computer's bottom. In one AGP slot sits an ATI Radeon 9600 Pro and there are three free PCI slots. A total of 8 memory slots for DDR PC3200 RAM sit together and must be filled in pairs - the computer uses memory interleaving which requires two identical DIMMs in the two memory banks.
The heatsinks on the G5 are enormous and our initial feeling is that it'll be a while before a viable solution for the Xserve and the Powerbook is found. If 9 fans and heatsinks the size of milk cartons are necessary in the Power Mac G5 then one wonders how it'd work to fit this into a 2.5" (my note: I don't understand this bit - when was the last time a Powerbook was 2.5" thick?) thick Powerbook.
There's space for one optical drive and Apple is shipping a 4x Superdrive with all PM G5s. A nice touch is the aluminium cover which smoothly vanishes downwards when the tray opens. Perfect for clipping your nails? We tried and the pressure of my fingers stopped the cover.
The G5 is being shipped with a Serial-ATA hard disk, a new standard which gives up to 150MB/s, a bit more than the earlier ATA/133. The biggest difference is that Serial-ATA uses a significantly smaller and more effective connection cable which doesn't impede the vitally important airflow in the computer. There's only one free space for an extra hard drive in the G5. The hard disk is held in place by special hard disk screws which cradle the drive. Apple excels here by storing the extra screws needed for installing another drive inside the computer beside the free space - no risk of losing a little plastic bag of screws!
On the computer's front are an easily-accessible Firewire 400 and a USB2 port. During our testing the keyboard was connected to the USB2 on the computer's front.
On the rear of the computer there are plugs for (from top to bottom) Airport, Bluetooh, optical in and out for sound, normal headphone jack, microphone, 2 x USB2, Firewire 400, Firewire 800, 10/100/1000Mbit Ethernet and modem. The graphics card has double outputs with one DVI and one ADC output.
Since the chassis is made of aluminium both the Airport and Bluetooth are mounted externally, otherwise the reception would have been significantly reduced (as was the case with the first generation titanium Powerbook G4s). This was done with two small plastic rods which are mounted simply on the back. One large Airport bar and a small bluetooth aerial look funny once mounted. Wonder if they're going to be big sellers on the part lists?
The sound level is surprisingly low. Upon starting the machine the whole fan system was on for a few seconds but then everything went completely quiet. I actually asked Lars-Åke Björk at Apple if the machine was even on! To my ears the computer is completely quiet, but of course you can hear a low whine if you put your ear next to the computer. Colour me impressed! Someone has taken notice of the criticism the racket the G4s made received.
Is the computer fast, then? Apple showed the same tests as Steve Jobs did at the keynote and it really does fly both in Final Cut 4 and Photoshop. For now the work is pushing ahead optimising OS X and a bunch of applications for the G4 and 64-bit operations. The machine we tested had 10.2.7 installed and Apple says that when 10.3 Panther is launched the performance will increase further through further optimisations.
Because our machine was a pre-release machine and the optimisations of both hardware and software are still in progress we can't publish the test results and comparisons with the G4 machine yet. In short, though, the computer feels really snappy (I'm translating "kvick" as "snappy" because I'm not sure of a perfect translation for it - besides, it's what we all want to read - again, any Swedes want to help here?) in OS X and in the few apps we got to test with it.
Within a few weeks we'll have one of the first production examples at 99mac and then we'll be able to release some speed tests using some popular apps.
A big thanks to MacSupport and Apple Sweden for their support.
Have a look at 60 G5 photos in our
gallery.