I'm currently trying to silence a SFF HP Compaq (dc7800) to use it as a HTPC. It's really nicely built, with intelligent airflow design, but comes with incredibly loud fans and/or lousy PWM algorithms.
Anyway, it looks like this inside
What I've done so far is, among other things,:
1) Replaced the 92 mm intake fan (to the far left in the beginning of the duct towards the CPU heatsink) with an Arctic Cooler F9 PWM.
2) Removed the 70x10 mm fan (on the opposite side of the CPU) heatsink.
3) Installed a passively cooled PCIe graphics card (in the PCIe slot on the right).
What I'm wondering is: was it a bad move to remove the 70 mm fan?
The logic behind the removal was that it was just blocking the way for the much more powerful 92 mm fan on the other side. Comparing the CFM values (which I don't know for the OEM 70 mm fan) would most certainly reveal that it moves much less air at comparable noise levels than the 92 mm Arctic Cooling fan.
But is the "air blocking theory" valid?
I can't really feel any air moving at all on the right side of the CPU heatsink when only running the 92 mm fan at acceptable noise levels. I gather it would be pretty nice to at least run the 70 mm fan at low speeds (using a fanmate), to blow some air over the passive PCIe graphics card.
So, ro sum it up:Will a 70 mm, low-RPM fan on the right of the heatsink, make the job harder/easier/no difference for the 92 mm fan on the other end of the air duct?
Thanks for your help!