More Advice Please

[miikman]

I have a couple new fans, a radeon 6870 and a solid state drive coming tomorrow.

My question is with my current CPU cooler and Case Fans:
Should I install another 120mm exhaust fan in the empty space? Or will it reduce the airflow through the CPU cooler? (here's a pic)



Thanks again for reading my post,

 

[catatafish]

I might worry that a pull through the top of the case right in front of that CPU cooler might disrput the air the CPU cooler is trying to pull through. My advise would be to leave the top fan out, check your temps and then add the top fan and see if it changes things. Air flow is a funny thing. It looks like you have a bottom fan that probably is blowing on that GPU pretty good already. Experimenting would be the only sure way to find out.

 

[QuietPC]

Do you happen to have or can you get an incense stick? Something that gives off a little smoke that you can use to track air flow? That way you can see where it goes and then make a judgement as to whether or not you need another fan and then whether it pushes or pulls. I don't think you will need to add one in the open slot but that's a way to check.

 

[miikman]

Hi, thanks for the replies.

I forgot to mention, with the setup I will have tomorrow my fans will be pushing/pulling 134CFM intake, and 143CFM exhaust. Would having a slight negative pressure help any?

I will check temps with and without a fan in that spot tomorrow and let you know.

I have an incense stick. I have smooth airflow now, in from the bottom front, curls around through CPU out the back/top. At least from what I can tell with the smoke off of this incense stick. I will check again tomorrow with the extra fan.

Also thought about adding a dust screen and a duct from that spot to CPU cooler, any thoughts? I know it looks like a duct wouldn't fit there, but I think enough modding could be done to make it look nice and function. Again if I try a duct I will test with and without but I imagine it would also disrupt some airflow from the rest of the case.

 

[catatafish]

You can't really judge by theoretical CFM. You don't exactly have an airtight machine there, not to mention all the cable and stuff jacking with the airflow....then there's the 10% +/- of the fan speed so what CFM you get from each fan is anyone's guess. You might be worrying about a problem you don't even have. The CPU and GPU temps will reveal all.

But now that you mention it, I would probably install the exhaust fan in that top spot just to keep dust and crap from falling in there and being sucked in by your CPU fan.

 

[miikman]

You are right about the CFM, and my worrying I think.

Anything at the top blocking dust is a must for me. I'd rather it be an exhaust than an intake, the duct is only a thought.

Thanks again, I will post my temps tomorrow.

 

[miikman]

Hello again,

Well I got my new fans and haven't seen much difference in CPU temps with a fan pushing exhaust in that open spot my CPU is running around 32°C idle and 45°C playing GTA IV at 1920x1080 on medium. Last night when I recorded temps I had 33°C idle/45°C load. Since FedEx burned me on two-day delivery of my video card I didn't record temps yet for my GPU.

Everything still looks okay smoke-wise, it takes a lot of smoke to actually see the flow but it still looks like the majority of the air is going through my CPU cooler and out the rear corner.

Conclusion:
I don't think there's enough pull out the top to really disrupt the airflow through my CPU cooler in my setup. I am leaving the second top exhaust fan in for now.

You both helped me tremendously, Thanks! Sorry to bother you with my preemptive worries. Next time I will wait until I actually have a problem.

 

[miikman]

Best answer selected by miikman.