First of all, let’s view the results of the Sapphire RADEON X800 XT wearing its standard cooling system:
Quite naturally, the temperatures are all right in the Idle mode. The card is practically noiseless, too, as the standard cooler is working at about 60% of its maximum speed when the GPU load is low.
In the Burn mode, however, the temperatures of the graphics processor and the memory chips grow up to 60-70°C. This is high, although not deadly. The fan accelerates to its maximum rpm rate in this mode, making quite an annoying sound.
Now, the same test, but with the Zalman ZM80D-HP installed:
The results suggest that the ZM80D-HP is worse than the stock cooling system as concerns cooling the RADEON X800 XT graphics card. The temperatures are slightly higher in the Idle mode compared to the first test, and quite dangerous in the Burn mode: your graphics processor and memory won’t last long working at 80-90°C.
Still, it’s too early to claim a failure of the ZM80D-HP. It is just not intended to work with graphics cards of the RADEON X800 XT class without additional cooling. Zalman highly recommends that you use an additional air cooler when installing the ZM80D-HP on graphics cards like NVIDIA GeForce FX 5800 and ATI RADEON 9800 PRO and faster. The company recommends that you purchase a ZM-OP1 cooler for that purpose.
I didn’t have a ZM-OP1 at hand during my tests, so I just took a low-speed 80mm fan, lowering its voltage from 12v to 7v.
That’s quite another story! With a little help from the additional low-speed fan, the ZM80D-HP easily beats the stock cooler in terms of efficiency as well as noise (the additional fan is not audible at all, while the standard cooler is wailing perceptibly under a load).