I'll admit to not having much experience with hot video cards. But please explain how the CPU in your new system, with it's fan at a fixed voltage, can remain at the same temperature with the ATI cooler blowing heat directly out of the case through it's own duct, as opposed to both Zalman coolers which just blow much of the heat around inside the case?
You would think while the ATI doesn't cool the video card as well, the CPU temperature would benefit. Am I missing something here?
We're not misreporting the results, in case that's what you're thinking. The simple answer: Your reasoning that the CPU must get cooler with the ATI cooler blowing air out is not supported by the results. If we must explain the results, I'd point to the fact that the CPU cooler benefits from a push-pull setup with 120mm fans on either side. They direct the air through the one exhaust from all the many open paths for cool intake airflow. Those factors appear to be enough to overcome whatever heat the Zalman fans may blow around in the case.
Note that even in the old VGA test bed, when ATITool only was applied to the X1950XTX with the Zalman 1000, the CPU temp stayed steady at 43C
regardless of the cooler's fan speed or GPU temp.
Another point: When the CPU and GPU are stressed simultaneously as it was here, although the total power drawn by the system goes up by almost 10% (compared to when just the GPU is stressed), the GPU appears to be getting a bit less stressed, and the CPU a bit more stressed. ie, this suggests the contribution of the GPU to the heat in the system is smaller, hence, its hot air "wash" less significant to the CPU.