HTPC airflow and PSU CFM?

luthierwnc

Distinguished
Apr 19, 2013
150
0
18,680
Hello All,

It worked out that our HTPC became a light-duty gaming computer. I want to improve the airflow but can't get any information on what kind of exhaust CFM the power supply puts out -- more on that in a minute.

The computer is in a Silverstone Grandia 5 HTPC box. It currently has 3 120mm fans. I have the two on the right side as intakes and the one on the left for exhaust. My wife plays a single incident of Eve Online with a single 27" monitor. There are times when the fans sound cranked but the temps are quite manageable. The computer is in a dusty location (dusty house) so part of the upgrade will be putting exterior filters on the side of the case to catch the pet hair and dust bunnies. I'll leave the interior filters in place too.

My plan is to add two 80mm exhaust fans on the back and have all three 120mm fans blowing in. Assuming the 120's are rated at 100 CFM (comparable Silverstone case fans free flowing) and the 80's at around half that, the pressure definitely be on the positive side. Good for contaminants but no real improvement in cooling. The GPU sits on edge creating what seems like a significant wind-block.

The wild card is the PSU fan. It has a 600w OCZ ModXStream Pro with a 135mm fan. I'm a bit surprised that PS makers don't offer much in the way of cubic feet per minute ratings. That fan by itself is probably around 110 CFM at the highest setting but the flow is also being bent sideways and forced through a grille. Ignoring interior pressure, let's say it puts out 60 CFM. That gets me 300 in vs. 160 out. It also puts positive airflow on that side of the card.

A) Any ideas on what the max CFM is on the PSU and
B) Does my proposed fan arrange make sense?

Thanks for looking and enjoy your weekend, sh

Windows 7 64-bit
i5-2500k (not overclocked)
16 GB RAM
256 GB SSD
2 TB Green spinner
GTX 660 GPU
 
Solution
I think you're over thinking this. The PSU fan isn't taken into consideration usually. It's there to get rid of its own heat.

You should be OK with 2 or 3 x 120mm fans blowing in from the sides and 2 x 80mm fans blowing out the back.

If you feel there's a problem, the best solution is to step up to an airier case eg Corsair 540.
I think you're over thinking this. The PSU fan isn't taken into consideration usually. It's there to get rid of its own heat.

You should be OK with 2 or 3 x 120mm fans blowing in from the sides and 2 x 80mm fans blowing out the back.

If you feel there's a problem, the best solution is to step up to an airier case eg Corsair 540.
 
Solution

luthierwnc

Distinguished
Apr 19, 2013
150
0
18,680
The additional fans are an afterthought. This started as a project to upgrade the SSD and put exterior filters on the intakes so I didn't have to clean the interior filters so often. I'm more concerned about dust than heat.

I actually built her a full gaming computer when I did this one but it sits in the office for bill paying. Go figure.

Thanks, sh