When you first remove the graphics accelerator from the foam packaging, the
first thing you’ll notice is a reminder on the anti-static bag.
Take note that the XFX NVIDIA GeForce 7800GTX 512MB will not run at full
speed properly without the insertion of the PCIe power connector.
If you are the type of geek who gets turned on by looking at the latest
hardware, a look at this engineering masterpiece is bound to get you into a
hopping frenzy (at least it did for me).
Let’s take a good look at the cooling mechanics of the XFX NVIDIA GeForce
7800GTX 512MB. Cooling is undertaken by the two-slot NVIDIA TM40 heatsink
The heat from the Graphics Processing Unit (GPU) die is transferred to the
copper base of the heatsink fan (HSF) via Thermal Interface Material (TIM,
commonly known is thermal paste, heatsink compound, gunk, goop or anything of
similar runny, gelatinous nature). Heat from the RAMs are transferred to a large
nickel-plated copper heatspreader which also holds the base of the heatspreader
for the GPU.
The heat from the base is further conducted via 4 large heatpipes to an array
of aluminium cooling fins. An 80mm fan in the center of the heatsink throws air
around in a radial pattern, cooling all 4 heatpipes and the fin array, thereby
bringing down the temperature of the GPU.
Hot air is partially exhausted out of the case though the
ventilation slots at the PCIe bracket.
On the bracket, you’ll also find dual DVI connection for simultaneous use of
two high definition displays with a single graphics accelerator.
Another portion of hot air moves through the plastic shroud
out into the case.
The fan’s rotational speed is controlled by PWM. You can see here that the
extra fourth pin on the fan connector runs a PWM signal. Thanks to the unique
and innovative cooling mechanism, the XFX NVIDIA GeForce 7800GTX 512MB ran at a
slight whisper even under the extreme stress we put it through.
The entire cooling setup is held securely to the PCB via spring loaded screws
that creates correct mounting pressure and maximal thermal contact.
Loaded by RTHDRIB, our test unit’s GPU temperature never exceeded 76 degrees
C in a non air-conditioned environment. Best of all, the TM40 did not make any
noise at all in it’s process of cooling the graphics accelerator.
Like many high-end graphic accelerators of the past and present, the XFX
NVIDIA GeForce 7800GTX 512MB is quite long at a whopping 23 cm.
Let’s zoom in on the PCB and its associated components.
The Printed Circuit Board used by the XFXNVIDIA GeForce 7800GTX is the P348
reference design from NVIDIA. Comprising of a 10 layer fibre glass board. The
main difference of the P348 PCB from the P347 design used on the NVIDIA GeForce
7800GTX 256MB lies in modifications for the new 1.1 ns 136 BGA GDDR3 RAM