# Case fan behind CPU socket worth it?



## btarunr (May 11, 2009)

My CM690 has provision for an 80mm fan right behind the CPU socket area:







A few questions:

-Will a fan there make a significant difference?
-Which direction should it blow? (there's no air-filter there so I'm assuming it blows outside the case, although illustrated otherwise)
-Does a fan pose EMI to the CPU/VRM?

Your thoughts please.


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## twicksisted (May 11, 2009)

by the looks of that fan in the pic (the position its in) it is blowing outwards from the mobo / cpu.
(if you spin the fan blades clockwise and imagine what direction its going to pull push from the picture)

I reckon it would help a bit as its moving air from under the board which would normally be a static area... but then again its an 80mm fan so itll be rather noisy.

I think if it were pulling cold air from outside the case uto under the motherboard it would make more of a difference... im not sure on the emi it would generate and how that could affect the cpu / vrms etc...


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## Mussels (May 11, 2009)

yes it can make a difference.

A fan on the back of my 8800GTX took 10C off that 90c monster.
Have it blow IN, so that its circulating air on the back of the mobo.

naw, no EMI risk at all. The extra airflow could help cool the things.

edit: That fans blowing IN, towards the CPU socket. they always blow to the flat side of the fan with the sticker - and thats the outside we're seeing.


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## alexp999 (May 11, 2009)

Dont forget it only takes a 15mm deep fan. They were a PIA to find when I was looking.

I have one in my FS thread if you're interested (see sig). Had it set as an exhaust fan @ 7v


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## Sir_Real (May 11, 2009)

Does that case side panel have a vent in the same place? I would imagine it has or its just poor design. If it hasnt then that fan isnt going to have any inlet/outlet & i'd not bother with it. 
However if there is a sidepanel vent there i'd defo have the fan suckin heat from the mobo & out the side panel. Might be worth wiring it to the 5volt line to keep noise to a min.


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## alexp999 (May 11, 2009)

Yeah it does have a vent there.

The idea is that it exhausts the hot air from under the mobo, and cools the back of the CPU socket. Great on my P5Q as it had heatsinks on the back of the board.


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## Mussels (May 11, 2009)

hell even without a vent, its circulating air in a total deadspot.

The idea here is to hit any hotspots and even out the temps - there isnt a huge amount of heat there that requires a fan to exhaust it outside the case, the idea is to get cold air in, and cool down whatever hotspots there may be.


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## h3llb3nd4 (May 11, 2009)

dude my case don't have those!! *brings out drills*


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## Sir_Real (May 11, 2009)

h3llb3nd4 said:


> dude my case don't have those!! *brings out drills*



Just remember to remove the mobo first hay


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## BumbleBee (May 11, 2009)

in my old 690 I had a 80mm Panaflo U1A blowing onto the back back of the socket because heat radiates up so there isn't any hot pockets just stale air underneath.


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## ShadowFold (May 11, 2009)

I could see if lowering temps if it was a high speed and blowing air out of the case. Blowing air onto a small area like that would only make it hotter, right?


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## BumbleBee (May 11, 2009)

why would it make it hotter?


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## DrPepper (May 11, 2009)

ShadowFold said:


> I could see if lowering temps if it was a high speed and blowing air out of the case. Blowing air onto a small area like that would only make it hotter, right?



Nope. Would be cooler but not as cool as if it was sucking air out.


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## Sir_Real (May 11, 2009)

ShadowFold said:


> I could see if lowering temps if it was a high speed and blowing air out of the case. Blowing air onto a small area like that would only make it hotter, right?



That would be true if you could get your fan to blow at mach 2 lol


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## Mussels (May 11, 2009)

Sir_Real said:


> That would be true if you could get your fan to blow at mack 2 lol



lol the friction from the airflow causing the metal to heat up.


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## BumbleBee (May 11, 2009)

exhausting air made no difference, by the way make sure it's a 15mm fan I learned the hard way.


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## alexp999 (May 11, 2009)

BumbleBee said:


> by the way make sure it's a 15mm fan I learned the hard way.



I mentioned that earlier


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## btarunr (May 11, 2009)

Still not clear as to which direction it should blow, I ordered this btw: http://www.sidewindercomputers.com/sandenpetace.html (Thanks for the offer Alex, those Yates look great).


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## BumbleBee (May 11, 2009)

oh sorry. didn't see. I cut the grill out 25mm will fit but it's really tight. I think Yate Loon makes a 80mm fan. Sanyo Denki is one of the best fan manufacturers.


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## alexp999 (May 11, 2009)

Sweet, it was such a pain trying to find a 80x80x*15* fan in the UK.

And it should be an exhaust bta

I have noticed my sniper acheives a smilar thing in a different way, by which the top fan overhangs the mobo tray.


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## Mussels (May 11, 2009)

btarunr said:


> Still not clear as to which direction it should blow, I ordered this btw: http://www.sidewindercomputers.com/sandenpetace.html (Thanks for the offer Alex, those Yates look great).



have it blow in. cool air to the back of the mobo.

It'll work its way around the case and vent out the back, not like you're sticking a jet turbine in there.


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## BumbleBee (May 11, 2009)

least Mussels agrees. I had a loop so I didn't really tell the difference between intake and exhaust but I belonged to a 690 club last year and most of us had ours on intake because one or two mentioned exhaust made no difference. if you really want to make a difference pop your hard drive rack out and turn it 90' the 690 hard drive rack is very similar to the one in HAF 932 in fact it is the same just bigger rectangular holes and different mounting bracket. hard drives get really hot (seagate in a 690) and the maximum operating temperature for a hard drive is 50-60'c before probability of failure. hard drive cooling is so overlooked.


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## sauria (Jun 1, 2014)

Do you know of newer cases that have a fan option in this area like the discontinued 690?  Thank you.


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## TheoneandonlyMrK (Jun 1, 2014)

Thanks for this thread guys I gave up on this mod last week because I bought 25mm fans like an ass but this thread makes me feel its worth a try.


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## sauria (Jun 2, 2014)

25mm?


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## Mussels (Jun 2, 2014)

5 year thread necro bummmmp!


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## sauria (Jun 2, 2014)

Sorry, I'd really like to get this case or one like it with a fan mount to cool the rear socket area.


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## Vario (Jun 6, 2014)

img credit: http://www.overclockers.com/forums/showthread.php?t=740816


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## Johan45 (Jun 6, 2014)

@Vario  thanks I'd recognize that anywhere. That's the back of my M5A and man that little fan worked wonders.


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## sauria (Jun 6, 2014)

That is great to know, just a 25mm fan helped!?


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## Johan45 (Jun 6, 2014)

sauria said:


> That is great to know, just a 25mm fan helped!?


 It was a 50mm /5000RPM chipset fan and could scream like a banshee when I was really pushing things. I had it wired to the CPU fan header and was controlled by the board.


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## sauria (Jun 6, 2014)

Thank you!


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## sauria (Jun 9, 2014)

I will try one of these to start:

http://www.amazon.com/dp/B005C31GIA/?tag=tec06d-20


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## Vario (Jun 9, 2014)

I have an Antec 300Two that has a vent hole behind the motherboard/cpu, you could try that.


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## THE_EGG (Jun 9, 2014)

Vario said:


> img credit: http://www.overclockers.com/forums/showthread.php?t=740816


It's so cute!


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