Estimate of CFM that 80mm GPU fan on MSI 7950 produces

[gregyoung14]

I've been doing a lot of research on airflow and CFM in regards to cooling annoying GPU rigs.

Anybody who has MSI 7950's, or any 7950's with similar 80mm fans, would like to take a stab at how much air those things move? (CFM)

Estimates at 50% 75% and 100% power.

I can't imagine these things move more than 20-35 CFM if not a lot less.

I have an idea to pretty much enclose my currently open design and then use several 120mm fans to intake on one side and exhaust on the other. Moving air works the best to cool these GPU heatsinks.

A little bit of testing quickly lets you know that just randomly blowing fans on these things can really be pointless.

For example I see a lot of people putting fans on top of there cards blowing down in between the cards. Now, I can't speak for every card design, but I have seen people do this specifically with MSI 7950 twin forzer III cards, which will in fact raise in temperature if air is blowed down on them.

It is more effective to blow air in between the cards from the back and front.

Due to the nature of my apartment (small 550sqft for college students really) I don't have much location for my rigs. I was trying to figure out how I could possibaly run them in my closet, I went so far as to get a 7,000 BTU portable air conditioner that was being exhausted through an air vent, that was no luck at all lol high gpu temps, ambient temperature was ridicoules.

I can run them in my living room, at 66c overclocked to high hell with just a single honeywell fan blowing on them with no issues. However, there is a lot of noise associated with that. and due to the fact that my cat needs to be able to go from room to room in the evening, I can't just shut the door. My bed is also 10ft away. And I'm a light sleeper. When I first built the rig I actually slept with ear plugs for a couple weeks lol

Anyhow, all advice and suggestions are welcomed. If anyone has any awesome secrets to cool temps and low noise levels, please share!!!

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[superfastkyle]

I don't think cfm is what you would need to worry about. Almost any 120mm fan will put out more cfm than a high end 80mm. But if your trying to modify the cooler the more important part would be to build air pressure so that the air actually goes through the fins on the heatsink vs around it

[deepceleron]

It is important to have case fans that do their job. Consider that the GPU fan sucks air from inside the case and blows it out the back slot of the card:

1. The hot air vented out the back should not be sucked back into the case - an empty card slot without a plate will allow hot air back into the case.
2. Power supply and case fans that blow out actually compete with the GPU fan. Consider a hypothetical super-strong case fan venting out - it will be pulling air into the case through any intake source available, including backwards through the GPU.

I found good success with 200mm 700RPM fans, they are quiet but move a lot of air. Set them up in the side of the case (or make a new case side out of posterboard with this 8" fan mounted) so they blow in, and they will enhance the GPU cooling by providing fresh air with the correct airflow direction. Ideally you'd have all case fans blowing in from the front and side, and the only outlet for air being through the GPU (and some CPU->Power supply airflow, but if your CPU is making much heat, you have a badly spec'd rig).

I actually have two of these fans I'm not using for rigs anymore that I could part with.