If the hot air is blowing into that area, why does it HAVE to be cooler?
That is my question on the 6990. How can there be a cold spot colder than the intake of the video card?
Also in terms of airflow, xbitlabs is saying the air is pulled through one heatsink to the other, then exhausted in the 6990. And the GPU temps they got seem to agree with that:
http://www.xbitlabs.com/articles/video/display/geforce-gtx-590_3.html#sect0
"The temperatures of the Radeon HD 6990’s GPUs differ by 10-12°C whereas the difference between the GPUs of the GeForce GTX 590 is only 2°C."
IR pics from hardware.fr
6970 CF:
Can you see the heat dumped into the HDD bay?
Observe the temp on the cable between 6970CF and 6990. With 6970CF, the cables are hot and heat moves through the cable into the HDD bay. It should be clear that the cable in HDD bay is hotter than its environment. 6990:
6990 is completely different, it is clear that 6990 dumps a lot of heat into the HDD bay.
What is interesting is the cable is cooler than its environment, indicating that somehow, heat were dumped away from the cables. In fact, it disappears in that cold spot. Those cables disappears because they get cooled off while they travel near the bottom front of the case.
Now look at the routing of the HDD cable it comes from inside the case (it gets difficult to describe things in 3D), out towards the camera, then back to the HDD. Under IR, the part where it is inside the case disappears because the temp is so low. This effect is very different from 6970CF and 590.
Now, 590
Since heat as no where to go, the entire HDD bay is heated up, and wires are actually cooler than its immediate environment, but not cold, just not as hot. Now compare it to the 6990, not only cables are cooler than 590, but even cooler than 6970CF where there are no front vent. In fact, although my claim is that there are no HDD fan on 590, there is airflow, which came off the vent. Immediate area around the vent when evenly heats up. Yes the 2 HDD cables appears to be cooler, but again, it is closer to the camera (3d). Back to 6990, there is also one known airflow, the front of the video card, but why didn't temp evens out? There appears to be a 30+c temp different between the top of the vent vs the bottom of the vent.
Dunno why my img links keep disappearing, I did referenced them...