Article: "PC airflow and heat - a cooling guide"

[billiardicus]

http://icrontic.com/articles/pc_airflow_heat_cooling_guide

I thought this was interesting. I am a mechanical engineer (but not an expert in heat transfer). The most effective cooling should occur when you have the highest air velocity through the CPU HS. If you have excessive exhaust ports, you could be reducing this velocity. I would guess that having a good HS and powerful HS fan would be the most effective way to cool the CPU (rather than having a sophisticated case fan setup).

Thoughts?

 

[phreejak]

Well, I would agree to a point. I think that, while having a supreme HSF combo is important, the jetstream within the case is very influential also. I agree that having a bazillion fans going every which-a-way can actually be counterproductive and even hinder the effectiveness of any HSF combo, having a goof directional flow and the least amount of obstruction to this flow is key.

People sometimes underestimate the importance of good wiring (cabling) in a case. Having a clear path for the air is defintely important. Then, if you can draw air from the front (down low) and, perhaps from the sides (say, directly on the GPU and additional intake) and draw (and exhaust it) through fans located on the upper half of the case (on top and rear) you would be draw heated air from its most natural position (in addition to drawing air over the HSF combo).

The article gave some very good points but I think it lacked in that it did not mention anything about cabling. Also, that case, as it was shown, is very barebones. nowadays, rigs are set up with one (or two or more) oversized videocards, sound card, TV Tuner cards, etc. Then, there are two (or more) HDDs and God knows whatever so the inside of the case can be alot mroe clutterred than the article gave allowances for.

 

[Evilonigiri]

IDE really blocked a ton of air when not rounded. Thank god for SATAs.

Very interesting article, I always knew that more fan isn't necessarily better, but I didn't know it would be by this much. Of course this will be different from case to case, so I don't think there will be a one size fit all solution.

 

[billiardicus]

I'm beginning to think that cases are for cosmetics only (unless you've got a box w/ rediculously poor air flow). Has anyone done any experiments (measured stressed temps before and after) with different cases/fans? A lot of the high end cases have lots of fans...I wonder if it makes a difference.

 

[Evilonigiri]

Oh it does, trust me. My CM Stacker 832 has 4 120mm side fans. After adding them in, I got a 5-10C drop in cpu temps and a 5C drop for my vidcard.

 

[Gone Cruising]

After getting frustrated about my temps I decided to experiment a little. I have a Thermaltake Armor+ VH600SWA, running 1000W psu, 2 x 9600 GT's in SLI, 5 HD's, 2 x optical, 4gb ram, 780i mobo, Asus Artctic Square cpu cooler and QX6700.

I was feeling all this heat pass through my hd's, over my gpu's and memory and get sucked into my cpu cooler and out the back. Case fans consisted of front 140mm, other side of hd's 120mm, 2 x 120mm bottom, 230mm side window and 120mm rear.

1.25V
Temps at stock idle(2.67) = 49C running Prime95 = 65C
1.35V
Temps OC'ed idle (3.33) = 56C running Prime 95 = 72C

I pulled everything out of the case and then reversed all the fans (including the cpu cooler) except the 2 120mm bottom. Now cool fresh air goes right into my cpu cooler, over my memory, out the side and front, while my bottom fans cool my gpu's.

Here's the difference:

1.25V
Stock idle = 39C running Prime 95 = 50C max
1.35V
OC'ed to 3.33 idle = 47C running Prime 95 = 60C max

I was amazed at the huge drop in temps. My Gpu's and HD's dropped also...not by much. Im just a happy camper!