Performance

After the initial installation the heatsink was immediately removed and the contact area was inspected. After loosening the screws that hold down the block, there was a strong suction between the block and the GPU, and it was difficult to take the block right off, I had to give it a little twist.

The thermal paste was spread well out, contact was good.

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For the overclocking tests, I used the latest ATITool 0.25 Beta 14.

The thermal diode integrated in the X800GT’s core was used to obtain temperatures. Load temperatures were measured after one hour of ATITool’s artifact scan test, idle temperatures after one hour of Windows desktop.

The fan on the X800GT varies its speeds according to temperature – to obtain “dynamic fan” values, I let the card adjust the fan speed on its own. For “fan 100%”, I used ATITool to force the speed to 100%.

The waterblock was tested with the following water loop:

• Eheim HPPS Plus
• Black Ice Xtreme II with 2 Sunon 7W fans
• Alphacool Nexxxos CPU block
• Thermaltake W2 block

The fans were controlled by a Zalman ZM-MFC1. On the low setting, I adjusted the variable resistors to their greatest resistance. When testing with both fans at 100%, I set the Zalman’s variable resistors to their lowest resistance value.

Because I used Arctic Silver Ceramique, I gave the paste three days of gaming in order for it to settle and achieve maximum performance.


I was also interested in the effect that adding a GPU block would have on CPU temperatures. Interestingly, the rise in CPU temperatures was minimal – only about 3°C.

From the graphs above, you can see that the W2 significantly decreases GPU temperatures. With the stock voltage, the GPU obviously ran out of breath – there was only a minimal difference in core clock between air and water cooling. However, as soon as I Vmodded the card, and gave the GPU more volts, the block was allowed to show its full potential, and allowed me to gain another 21 MHz at a safe voltage.

I was also interested to see the restriction of this waterblock. In order to obtain flow readings, I used a Siemens Megatron 2 flowmeter. While its accuracy is not ideal, it does give some sort of idea about flow rate.


From the results we can see that the block decreases water flow by about 60%. While this is certainly not the best, it could have been worse (for comparison, some full cover blocks restrict water flow by up to 70%).