Experiment: Do Expansion Cards Have an Effect on GPU Temperatures?

[XacTactX]

I originally wrote all of this plus some pertinent info in someone's FS thread to let the person know about this, and I thought you all might find it interesting. Hope you like it.

I have a Radeon HD 4850 (reference design and cooler), and I recently bought several sound cards so I could experiment with them. With my HD 4850 in slot 1 in all situations, I've had sound cards positioned in several ways:

Test setup:
NZXT Lexa S (all stock fans)
Zalman ZM-MFC1 Plus @ 0%
Radeon HD 4850 in slot 1 (reference PCB and heatsink, AS5 in all cases)

setup 1
slot 2: Xonar DG
slot 3: SB Audigy

Idle: 63-64* C @ 42-45% fan

setup 2
slot3: SB Audigy 2 ZS

Idle: 58-59* C @ 39% fan

setup 3
slot 3: Asus Xonar DG

Idle: 55-56* C @ 36-38% fan

My point is: If your case has a side intake, like mine does, which gives the GPU the majority of its fresh air, placing a full-size expansion card adjacent to your GPU will probably cause a significant increase in your GPU's operating temperatures and/or fan speed. Low-profile expansion cards (like the Xonar DG) seem to minimize this problem compared to their full-size counterparts.

EDIT: I would also add that setup 3 was the first one that I performed, after which I picked up the case and shuffled it ~100 steps up and down a flight of stairs. Does that have an effect on the thermal grease's ability to fill the imperfections? That's the only thing I can imagine if anyone thinks airflow is not the only factor at play. And the A2 ZS was the last setup that I tried, again shuffling the case around, and I'm currently using it.

 

[Janus67]

I would generally think it would be based on the amount of heat that is output by the expansion card (not much) and the viability of pulling in fresh cool air into the cooler. It also depends on the fan setup/design of the card and if it is made to pull in air and push out the back or just refresh the air around the card.