Installing the G03 Retainers:
From the back side of the card, press the supplied spring-loaded retainers in the two holes shown below. (The photo shows them already installed.)

G03 retainers Installed (Backside of card)

Prepping the Verax G03 Heatsink:
Since the G03 heatsink contact (bottom) surface may have oils or other contaminants on it from handling, clean (scrub) the surface with Alcohol and a clean, lint-free cloth and let dry. Then using either rubber gloves (or a new sandwich baggie over your fingers) to prevent getting oils on the surface, massage some thermal compound into the (sandblasted on the G03) contact surface. I used Artic Silver, not the supplied white paste however. I also had some phase-change (i.e. melts to seal in use) high-efficiency thermal gaskets from GigaDesign handy, so I applied that to the GPU chip rather than the liquid thermal compound so the photo below looks differently than if I'd used paste. (I trimmed a bit of the excess shown in the photo.)

Thermal Gasket/Compound Applied to GPU

Carefully lower the heatsink over the GPU while aligning the retaining pin holes in the heatsink with the retainers sticking up through the board. Try to keep the Heatsink off the GPU chip surface until you have the alignment correct to avoid smearing away the thermal compound. (Pressing on the retaining pins behind the board will raise them up to help with alignment.)
Once the retaining pins are aligned with the mating holes in the heatsink - while holding the heatsink firmly pressing (hard) on the retaining pins on the back of the board until they 'pop' through the heatsink.

Checking HS/GPU Contact:
After both pins were through the heatsink, I then held the board up to a light source to check that the GPU center contact patch was contacting the heatsink and not just the chip's perimeter border wall/strain relief. (Some Cooler MFR's note the GPU contact patch may be below flush with the boarder "fence" of the chip. I've seen some suggest removing the 'wall' or ensuring adequate buildup of thermal material on the GPU chip to ensure good contact. I didn't try removing the border 'wall' (strain relief) around this chip to see if that was even possible, since it was not necessary on this sample.)
It's not visible in the photo below, but when placed in front of a light source I could see a tiny gap around the border of the GPU chip and the heastink and contact (no gap) on the center GPU patch/Heatsink mating area.

Side View of Installed Heatsink

G03 Power Cable:
Now that the G03 Heatsink is installed, connect the supplied Y-adapter cable to the fan's 3-pin power cable. (Verax and some other fan vendors say their fans draw more power than the on-card OEM fan power connection can source.)

G03 Supplied Power Cable/Adapter

Note: For retail 9800 Pro cards where you already have a Y-adapter used (for basic card power), I'd be tempted to solder the fan power connections to the pads for the on-card (Molex) power connector to keep things cleaner cable-wise.

Verax G03 Fan/HS Kit Installed on OEM 9800 Pro

After a quick visual check of the work, it's time to install the card in the G5 and see just how quiet the G03 really is.

Fan Power Connection:
The supplied G03 power cable/Y adapter must be connected to a standard (Molex 4pin) power supply plug. In the G5, as noted in my previous article on G5 tests with the retail Radeon 9800 Pro (which also requires this power connection but for the basic card power), the only plug in the G5 for this is already connected to the CD/Optical drive. (ATI later posted an illustrated 9800 Pro/G5 install guide that covers the power cable connection.) You have to remove the G5's Optical drive (2 levers, then slides out) and disconnect the power cable from the drive, then plug that into the Y adapter. Then the Y adapter's plug connects to the Optical drive. (I had already pulled the optical drive cable into the lower PCI slot area and used the retail 9800's Y adapter cable which I connected the G03 cable to, but you may want to try just routing the Y adapter up into the Optical bay area instead to reduce clutter. Places like Radio Shack sell adhesive backed cable clamps and cable ties that are handy to retain cables out of the way.

As you can see in the photo, the G03 cooler is taller than the OEM one and therefore blocks the adjacent PCI slot in the G5. But it's so quiet compared to the OEM fan on my 9800 card it's a welcome trade-off.

OEM 9800 Pro w/G03 Installed in G5 System

When first powering on the G5, the Verax G03 was so quiet I had to touch the fan just to verify it was running. Not cheap but definitely a night-and-day difference from the OEM fan (which for my sample sounded like a cross between dremel tool and a slightly muffled dentist's drill).

Where to Buy:
For USA customers, you can order from www.veraxfans.com, otherwise visit the primary website at www.verax.de which also has a "dealers" page. Both sites have links to the G03 product page.