Anyone done this?

Grov · Sep 23, 2004

http://www.overclockers.com/tips1177/

Suppose it makes sense, and easy to do? What you guys reckon.

mantrogo · Sep 23, 2004

I've seen various reports on putting a blowhole in behind the mobo. Some people report really good results, others nothing. Part of the prob is that the heat conductivity of the material that mobos are made of isn't that high - so the effect would generally not tend to be that large if cooling that spot on the mobo is the only thing changed - ie it's not just that you're improving overall case airflow.

Best way to see if you're getting a real effect, rather than just screwing up the sensors, is to see whether you get higher stable oc's? To test it, why not rig up a cardboard case side, put in a hole and fan and see how it goes - before you dremel a hole in your case!

One other thing to bear in mind is that the fan will blow directly onto a flat surface - mucho noise.

Grov · Sep 23, 2004

Yeah, good point about the noise, don't think ill bother.

Evil T C · Sep 23, 2004

i read recently that as much as 30% of heat produced from your cpu is transferred through the back of your mobo so cooling this could well be a good idea

Electron Chaser · Sep 23, 2004

yes I have done this. Noise is not an issue though.

This is the fan I used.

Zalman ZM-OP1 80mm X 15mm fan

archilochus · Sep 23, 2004

Did the same as EC, but used a 92mm Panaflo U1A...68.80 cfm @ full tilt...Fan is filtered too.

I don't run it @ full tilt unless it's 30°C in this room... :drool:

It's good for a couple of degrees drop in system temps...

please don't quote my pic.

edwardaune · Sep 23, 2004

Electron Chaser said:
yes I have done this. Noise is not an issue though.

This is the fan I used.

Zalman ZM-OP1 80mm X 15mm fan

What kind of results did you see?

clocker2 · Sep 23, 2004

Many of us have tried this mod and it is undeniably effective.
The best results come from cutting the largest hole possible in the mobo wall ( the better to expose the northbridge, DIMM slots and MOSFETs) and using a 120 fan on the sidepanel.
Mounting the fan externally moves it far enough away from the back of the board so it has some room to breathe ( especially at slower speeds ) and blowback is minimized.
I consider this mod to be an essential step in establishing an effective cooling solution...a no-brainer, really.

mtb856 · Sep 23, 2004

Me too. Me too!!!!

It dropped my load temps by about 4°C and while I was at it I made some more holes so I could route my wires behind the mobo plate. I used a high pressure 92mm fan, so to eliminate the noise from the fan being so close to the mobo ( backpressure made the fan whine) I made a duct from the shell of a 92mm fan.

Electron Chaser · Sep 23, 2004

edwardaune said:
What kind of results did you see?

I didn't see any difference in CPU temp. However my Case and NB temp did drop about 1 C. Perhaps if I used a larger fan like Arch did I may get a better result.

mribnik · Sep 23, 2004

And this works better as an intake or an exhaust?

eh, bah, I bought a retention bracket off ebay from EC's recommendation. It has a backing plate behind the mobo. Does that render this mod pretty much useless for me? The backing plate being right where I'd want to blow air and all...

edit again: i'm stupid and noticed the above pictures of systems with backing plates as well, perhaps it's worth a try.

Evil T C · Sep 23, 2004

hmm i was just about to ask the same question....

with a plate like you get with heavy heatsinks, ie the sp94, do you still get a good result?

does the plate transfer heat well enough even though it doesnt come in contact with the back of the mobo or will it limit the effectiveness of the fan?

lilneel12 · Sep 23, 2004

i just did it as a test, since i had a hole under my mb cpu socket already. with a 70mm fan that blows a good amount of air. my cpu temps dropped maybe 1c degree at full load using dual prime 95's, but my PWM or mosfet temps dropped 8c at full load. As soon as i turned the fan off at full load, my mosfet temps went to 40C with the fan on they were at 31-32c.

pirred908 · Sep 23, 2004

What is PWM?

mtb856 · Sep 23, 2004

Pulse-width modulator I think

Electron Chaser · Sep 23, 2004

mribnik said:
And this works better as an intake or an exhaust?

eh, bah, I bought a retention bracket off ebay from EC's recommendation. It has a backing plate behind the mobo. Does that render this mod pretty much useless for me? The backing plate being right where I'd want to blow air and all...

edit again: i'm stupid and noticed the above pictures of systems with backing plates as well, perhaps it's worth a try.

I use it as an intake and blow into the case. As far as the bracket is concerned the center area of that bracket is open. which is the area that surrounds the CPU socket. Which is better then the majority of the other backing plates out there.

I think for people that don't move a lot of air through their case this will help a lot. I'm a freak for CFMs so it didn't make that big of a difference for me since I move over 1K CFM a minute through my case.

murdok5 · Sep 24, 2004

anyone try putting a lil heatsink there? then a fan? i kno there isnt much room, but if u already got fans sticking out of case...why not try it

Mike

tom_ed1987 · Sep 24, 2004

yes i have thought about attaching heatsinks to the reverse of a mobo, especially on the reverse of the mosfet's as they seem to put most heat out of the bottom of them and through the mobo.

archilochus · Sep 24, 2004

The main idea was to get the heated air from behind the mobo moving...Get it into the flow and out of the case...
I had planned to use the neo back plate from Thermalright, so the socket would be expossed to the air from the fan...
Then MattMolson mounted his SP-97 with PCB washers he made..Omitting the SP-97's back plate...It's all in the Modding Xaser III thread..

I've yet to do anything with the back plate issue, because I'm happy with my temps as they are...

Electron Chaser · Sep 24, 2004

murdok5 said:
anyone try putting a lil heatsink there? then a fan? i kno there isnt much room, but if u already got fans sticking out of case...why not try it

Mike

Me personally I won't too many bare solder connectors back thare that don't give me a warm and fuzzy to start mounting HSs on. Not to mention the clearance is tight as it is.

Anyone done this?

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