New PC time... fans, that's the hardest part.

[pfarber]

Well its time to upgrade from the ASUS G74 to a real PC again. The G74 is an awesome rig, but its just to clumsy to have it and a 23 inch monitor on my desk... plus I needed a new video card to play games.

The hardest part? The damn case fans. Most PCs don't have the right PWM controlled fans for the BIOS to control the fan RPMs. Usually the CPU fan is PWM, but case fans are single speed devices... UNLESS you either buy a PWM fan AND the motherboard has PWM output (with pulse.. typically a 4 pin connector) or you buy a fan controller... and then its purely up to you to set the RPMs via a rheostat.

Enter the Cool Master JetFlo 120. $18 each (that's 3x the cost of dumb case fans) and I was ready to not buy those and opt for a manual speed control and 4 dumb fans. But when I had everything in my shopping cart (Amazon) I noticed that the 4 dumb fans PLUS the fan controller was MORE than two PWM fans (the cool masters) and two dumb fans!

So I avoided a costly mistake and would have had to live with fans that are screaming full blast, of have to tinker with RPM speeds.

Now I can run a BIOS monitoring program to cycle the PWM fans as needed.

The case comes with one dumb fan in the front. I am adding a second dumb fan up front (with blue LEDs to signify 'cold air in') and the second dumb fan will exhaust out of the upper rear (the CPU fan fill blow right into it. Its got red LEDs to signify 'hot air' (ain't I clever?). One PWM fan will go on the side cover directly over the GPU (Nvidia Gtx 770) also with red LEDs, and the last PWM fan will go at the very top of the case, with red LEDs.

Since I plan to OC the GPU/CPU moving air is gonna be a factor.

It took me about 30 minutes to spec out the PC, and two days to get the fans right.

[pfarber]

Hmmm... well I just got schooled on case fans. I have always placed the side case fan so it drew air OUT of the case.. since the GPU is typically right under it, I figured that pulling air UP and OFF the GPU was proper.

Seems that many believe that the side case fan should push air INTO the case, ONTO the GPU, to help cooling. I'm not sure if that is right either. High end GPUs have 2-3 fans on its one heatsink. Typically the fins are vertical (as seen from the side case fans point of view), as on the Gtx 770 I bought:

gtx770.JPG (38.52 KiB) Viewed 2395 times

So if I blow air DOWN onto the card (well, actually from the SIDE) I will be negating the cooling flow from the 3 on card fans. The Cool Master fans are rated at 95 CFM at max RPM... more than enough to overcome the on card fans.

The only positive thing is that changing the direction of air on the side case fan is super easy.