External Exhaust Fan by PCIe Slots

[ShiWarrior]

ah, just found this :

 

[SpudMaster]

Nope once I established that the graphics card really didn't benefit from additional airflow I stopped experimenting and just set the lower intake and exhaust to about 600rpm so they are silent but providing a decent through flow of air.

Having the lower fans maxed out made no difference to the GPU but the CPU benefitted by a couple of degrees I'm guessing that the extra turbulence from below diluted the hot air from the back of the GPU but as the CPU is undervolted and has a negative PBO curve it runs cool enough anyhow.

Now you've got the fan you might aswell give it ago as an intake. The problem you have when its an exhaust is the gpu fans are sucking air in the opposite direction so both fans are competing for the air. As in intake it will atleast be providing cool air to the gpu fans

 

[bfar]

The new Lian Li 216 case has a bracket for this (although you need to supply your own fan).

Some of the reviewers tried it with and without the fan and it didn't seem make a huge difference. I think the orientation of the heatsink fins on the GPU allowing air to exhaust out the back has some effect. Unfortunately I think your heatsink has fins running perpendicular to the pci-e port (if that makes sense) so the fan won't be as useful as it perhaps could be.

I wonder if the GPU intakes are pulling in the cool air before it reaches the rear of the case? The GPU is probably doing the job of that rear fan and pulling the cool air to where it actually needs to be.

 

[PieEater]

Now you've got the fan you might aswell give it ago as an intake. The problem you have when its an exhaust is the gpu fans are sucking air in the opposite direction so both fans are competing for the air. As in intake it will atleast be providing cool air to the gpu fans

I wonder if the GPU intakes are pulling in the cool air before it reaches the rear of the case? The GPU is probably doing the job of that rear fan and pulling the cool air to where it actually needs to be.

I have a 140mm intake feeding fresh air directly to the GPU cooler the idea of the exhaust was to ensure a throughflow so that the fresh air from the front was pulled towards the back of the case allowing the GPU cooler fans to access it. I may try the rear fan as an intake as and when I have the time and motivation possibly in the summer when things start to heat up but right now everything is running pretty cool