ASUS EN8800GTX Aquatank
Author: Luka Rakamaric
Date: 15 Apr 2007

The 8800GTX, with its enormous transistor count, over two times the number on the previous generation?s flagships from both manufacturers, is not easy to cool down. The stock cooler, while covering the whole card and being two slot thick, could only get the card to around 80 degrees in a closed case during a stress test. Although the thermal limit of the chip is over 100 degrees, it is still not desirable to get to such high numbers, especially if you plan to overclock the card. Some NVIDIA partners opted to go for a Peltier device, like Calibre. It offers improved transfer of heat from the GPU to the heatsink fins. ASUS decided to implement a water cooling solution on this limited-edition-and-already-EOL card. ASUS used Thermaltake?s Tide Water cooling for 8800GTX, unlike EVGA that whose Black Pearl cards are made in cooperation with Innovatek.

Improved cooling always brings the next logical question, what about overclocking. ASUS didn?t leave much room to overclock, as the card is already working at 630 MHz, which is a full 55 MHz above the stock speed, or almost 10%. With a top of the line card, that is supposed to be the best you can extract from the chip, a 10% increase in core clock without changing the voltage is really impressive. As we will explain later, the 630 MHz is not exactly 630, but slightly lower. The memory speed is also impressive, as the card has memory working at 1030 MHz, which is 130 MHz above the stock speed. With DDR the effective clock is 2060 MHz. We feel the need to point out that X1950XTX has a stock memory speed of 2000 MHz, but using GDDR4 memory, while 8800GTX uses GDDR3.

To dissipate this much heat produced by the overclocked GPU and memory, ASUS uses an interesting solution based on both water cooling and active air cooling. The GPU and memory chips are covered with a black aluminium board with small fins, but the middle is copper with an integrated water block. The fan on the card directs the air to the small fins, so memory chips are cooled very well. The water block is connected with rubber pipes to the other part of the cooler, a giant two slot combination of a pump, a reservoir and a radiator. The same solution, only single slot, appeared on Sapphires line of Toxic graphic cards, but they didn?t have active memory cooling. The fan on the radiator has two working modes, normal and silent. Altough we can understand that overclocked cards are not meant to be silent, if you use the normal mode, it will be significantly louder than the stock air cooler. Fortunately ,the difference between the two settings is only a couple of degrees, so you will not be limited if you choose silence.