Zalman ZM-80C Heatpipe

Zalman ZM-80C Heatpipe


The above picture clearly shows that the contact between heatsink and core is good. The pressure was enough to make the ATi logo on the core shine through the thin layer of thermal paste that was covering the core prior to mounting. The bottom surface of the heatsink is designed properly for Radeon 9500 / 9700 cards where the core is a bit lower than the surrounding metal shim.

For the overclocking tests I used my ATITool overclocking utility version 0.0.17. ATITool has the unique ability to detect artifacts, or flaws, in a rendered image. As defined by ATITool, the maximum stable overclock on a card is the speed at which it is able to consistently (15 minutes in this test) produce no errors, or artifacts. ATITool detects ANY artifacts, even ones which will not be visible in game. Using the human eye to detect artifacts introduces subjectivity into the test, so despite the fact that an ATITool tested overclock will be characteristically lower than a human one, I will use this.

Temperature was measured with one case side open by putting a thermal probe on the backside of the Radeon 9800 Pro opposite of where the GPU is. Idle temperature was measured after letting Windows sit one hour at the desktop. Load temperature was measured after running 3DMark2001 looped for one hour. Both at the card's default clock of 380 / 340 Mhz.

Arctic Silver 5 was used as thermal interface material for the GPU core in all installations. I used Arctic Silver 3 for all other contact surfaces of the Zalman cooler.

A 7V setting is possible by connecting the fan connector's black wire to the PSU's 5V output, and the fan connector's red wire to the PSU's 12V output (12V - 5V = 7 V).

Radeon 9800 Pro Maximum
Core Clock
Sound level Temperature
Stock cooler

416 Mhz

Zalman ZM-80C passive 401 MhzInaudible75°C53°C
Zalman ZM-80C + OP-1 5V419 Mhz Almost inaudible45°C32°C
Zalman ZM-80C + OP-1 7V420 Mhz Quiet40°C31°C
Zalman ZM-80C + OP-1 12V423 Mhz Noisy35°C29°C
Watercooling (Water ~33°C) 440 Mhz Inaudible37°C35°C

While running the ZM-80C passive gives you a completely quiet solution, the temperatures, especially under load, are unacceptable. Don't forget that the temperature was measured on the card's backside so actual core temperature is even higher. Zalman does recommend the addon fan OP-1 for all 9800 cards.

With the OP-1 fan-addon the temperatures were good, but the fan is too loud at its 12V setting. The 5V setting seems to be the way to go here. "Modding" the fan to use 7V does not really help much in terms of overclocking, and 5°C more on the core under load won't really matter.

This cooling device is definitely not for someone seeking to overclock their card to higher levels than with the stock cooler. The best use of it in my opinion is for systems that you want to be quiet. That's why I will put my ZM-80C on the 9800 AIW in my Home Theater PC, together with a slow-running, temperature controlled fan which won't start before the heatsink reaches a temperature of about 60°C. This should be enough for all media playback where silence is important, and good enough for occasional gaming where the game "distracts" you from hearing the fan.

Value and Conclusion

Heatpipe technology and big heatsinks sure are nice looking. I don't really like the look of the fan addon though.
Ease of use6.5
Installation is quite complicated and it's easy to mess up. The screwdriver is a gimmick that most users already have anyway. Great that it fits most video cards.
Performance is ok when used together with the fan addon. Complete silence requires either a sophisticated air flow design or a low-end video card.
All parts look to be of good quality and are well manufactured. Giving the user spare parts is a great idea, especially since the parts are small and easily lost.
The fan addon is a must unless you are running on an old video card or have extremely good airflow - this adds another USD 10 to the ZM-80C's price tag. Other cooling solutions can be had for less.
The Bottom Line8.0