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Case fan behind CPU socket worth it?

btarunr

btarunr

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System Specs
System Name RBMK-1000
Processor AMD Ryzen 7 5700G
Motherboard Gigabyte B550 AORUS Elite V2
Cooling DeepCool Gammax L240 V2
Memory 2x 16GB DDR4-3200
Video Card(s) Galax RTX 4070 Ti EX
Storage Samsung 990 1TB
Display(s) BenQ 1440p 60 Hz 27-inch
Case Corsair Carbide 100R
Audio Device(s) ASUS SupremeFX S1220A
Power Supply Cooler Master MWE Gold 650W
Mouse ASUS ROG Strix Impact
Keyboard Gamdias Hermes E2
Software Windows 11 Pro
My CM690 has provision for an 80mm fan right behind the CPU socket area:

file1200973996213.jpg


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.
 
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...
 
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.
 
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
 
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.
 
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.
 
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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dude my case don't have those!! *brings out drills*
 
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.
 
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?
 
why would it make it hotter?
 
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?
Click to expand...

Nope. Would be cooler but not as cool as if it was sucking air out.
 
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?
Click to expand...

That would be true if you could get your fan to blow at mach 2 lol
 
Sir_Real said:
That would be true if you could get your fan to blow at mack 2 lol
Click to expand...

lol the friction from the airflow causing the metal to heat up.
 
exhausting air made no difference, by the way make sure it's a 15mm fan I learned the hard way.
 
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.
 
Sweet, it was such a pain trying to find a 80x80x15 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.
 
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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Do you know of newer cases that have a fan option in this area like the discontinued 690? Thank you.
 
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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