Unique cooling

While ASUS’ Extreme N7800 GTX TOP looks very much unlike any other GeForce 7800 GTX card on the market, it’s actually fundamentally a reference design underneath the card’s cooling. ASUS doesn’t deviate from NVIDIA’s reference board design for the GeForce 7800 GTX, all they’ve done is bumped up the core and memory clock frequencies by default, and swapped out the stock NVIDIA cooling for a much more robust unit. We’ll start there first.

For their Extreme N7800 GTX TOP, ASUS opted to go with a heatsink/fan unit from Arctic Cooling, their NV Silencer 5. Arctic Cooling’s VGA Silencer coolers are well known for their unique ability to combine excellent thermal performance while running nearly silent, which is why enthusiasts have embraced them so quickly. The NV Silencer 5 cooling present on the Extreme N7800 GTX TOP is hardly audible over the CPU fan.

Copper plate cools the GPU

The cooler starts with a copper base plate, which rests over the GeForce 7800 GTX’s G70 GPU and its accompanying GDDR3 memory. Arctic Cooling uses copper instead of aluminum (which is used on the reference GeForce 7800 GTX cooler) because it conducts heat better than aluminum. With more heat coming off the GPU, Arctic Cooling needs to transfer that heat somewhere – this is where the Extreme N7800 GTX TOP’s dual graphics slot requirement comes in, as the NV Silencer 5 uses a large aluminum heatsink to accomplish this. The heatsink measures roughly 2.75”W x 2.9”L, with a height of about 1”.

This is just over twice the height of the stock GeForce 7800 GTX heatsink NVIDIA’s board partners use on their first-generation 7800 GTX cards, while the entire cooler is about ½” taller than the heatsink/fan unit used on GeForce 6800 Ultra cards.

Air passes from fan, past heatsink, and out the front of the card outside case

Bracket acts as additional cooling

As a result, the Extreme N7800 GTX TOP’s aluminum heatsink swallows up the slot directly adjacent to the graphics card. This is where you could run into problems with some motherboards if you plan on running two Extreme N7800 GTX TOP cards in an SLI configuration. The card’s cooler is so large that you’re really going to need just a hair over 2” of clearance between the bottom of the first x16 PCI-E slot, and the top of the second slot to seat two Extreme N7800 GTX TOP cards comfortably for SLI. ASUS’ own nForce4 SLI boards provide this, but unfortunately most other SLI boards don’t. This is something you’re going to have to keep in mind if you plan on pairing two Extreme N7800 GTX TOP cards together.

Thermal pads are used to transfer heat from the memory modules on the top of the Extreme N7800 GTX TOP board to the NV Silencer 5’s copper plate, heat from the GPU and memory then passes up the copper plate to the aluminum heatsink, whose large fins increase its surface area and thus its effectiveness. The heat then passes up the heatsink’s fins where it’s ultimately drawn outside your system’s case for better ventilation.

Close-up shot of the fan

Here you can see the aluminum heatsink above copper plate

Stock NVIDIA cooling on the RAM

Arctic Cooling uses a large fan to accomplish this. The fan looks large and daunting, but its actually due to its size that it’s fairly quiet. Since the fan sports large plastic fins, the fan’s motor doesn’t have to crank up to high RPMs: Arctic Cooling’s NV Silencer 5 runs at 2,000 RPMs, about half that of your typical graphics card’s fan. Besides quieter operation, the other benefit of running at lower RPMs is that the fan’s motor lasts longer. Artic Cooling warranties their NV Silencer 5 fan for six years.