SLI Air-cooling


Limp Gawd
Feb 15, 2006
Hi all

Just got another MSI GTX680-Twin Frozr 4G (4gig)card.

I have a cooling question..I guess the most important thing is to have a good side CASE fan blowing in cool air on Cards...Im running a NZXT case with 2-120 mm front fans ,1-140 side(that came with the case) and 1-120 exhaust. thinking of adding another 120 top exhaust..not sure I need it..

Any input would be great..........
Try with what you have now....It wont hurt to add one, but see if you do before you get another fan.
Important thing is to not have more exhaust than intake. If you have more exhaust than intake you get negative pressure, then the case will start pulling air in from every nook and cranny it can, including areas that may disturb the current airflow and provide airflow in unneeded areas like the 5.25" drive bays. This may also result in dust buildup in the nook and crannies.

Right now you have 3 intake fans, 1 exhaust, and 1 fan in the PSU exhausting air. That's a 1.5:1 ratio of intake to exhaust.

At most I would add 1 more exhaust fan at the top nearest the back of the case and running at low speed. Beyond that you will see diminishing returns and would have to add more intakes to compensate. Do not mount another exhaust fan any more forward on the case or else you risk starving the CPU heatsink of cold air coming in from the front of the case. I would definitely crank up the speed on the side intake fan and the 120mm exhaust fan on the back panel since it is the closest exhaust fan nearest those cards and it will suck out some (but not all) of the hot GPU air before it goes into the CPU heatsink.
One step at a time. Just remember that there's multiple factors involved in cooling aside from the raw CFM ratings of your fans. Unobstructed airflow can be *huge*.