CPU heatsink fan questions

[Shaved Ape]

Please don't berate me. I have a Dell Dimension 8300 which is almost three years old. Lately I've been tinkering around with adding intake fans as it previously had none which has helped a lot with the noise (generated by the CPU fan workng overtime).

However, I also noticed the CPU heatsink dissipates hot air by exhausting through a small duct. Not such a bad thing you may think, but wouldn't it work better if the fan was pulling cool air in over the heatsink, rather than just moving the hot air out (with little to no chance of using ambient coolish air to help cool down the heatsink)?

I thought of turning the orientation of the fan around so it pulls air in, but I would like to get some advice just in case there is something I'm missing here.

 

[suszterpatt]

Most heatsinks are indeed designed to blow air onto the heatsink... you could try swapping the fan and see if it performs any better, but there's no real guarantee.

 

[GalvanizedYankee]

Do not turn the CPU's fan over !!

It is made to suck air off the sink, then duct it to the rear of the case.

Go to www.sidewindercomputers.com, buy a NMB 92x32 thermally controlled fan for $5. This is the
slow speed fan for your Dell. It will run somewhat quieter than the fan on it now but it still
tops out at 70cfm@43dBA. Fan speed is controlled by a hub mounted thermistor. If the fan
is installed to blow the CPU will overheat and throttle back to a stop.


...Galvanized

 

[Shaved Ape]

Thanks for the advice! It's just that the location of the fan is quite a fair distance from the heatsink (it's not even parrallel to it) and I just get the feeling it's performance could be better if the fan was sucking air right off the heatsink rather than being at the end of the chain, so to speak, where the potential to draw air must be affected.

 

[Jhhnn]

I'd try galvanized yankee's recommendation, provided that the referenced fan is the right size... The temp sensor on your fan is probably borked, and as a failsafe they go to max rpm when that happens. Dells are usually quiet, if they're working right...