Top mounting a PSU in a Lian Li PC-A71F

[95thRifles]

I'm looking at a rebuild of my PC and as part of this I'll be modding my case which will include relocating my PSU (thinking of either Corsair AX750/850) to top to allow for bottom mounted rads. Question is do I

a) mount it with fan (intake) facing down?
Pros - No dust will enter PSU, no modding of top panel of case
Cons - PSU will run hot as it will be intaking air from PC rather than externally, however having read reviews the PSU does perform well under high temps, eg JonnyGurus hotbox test

b) mount it with fan facing up?
Pros - Can be on separate air loop which will run cool, I'd add a fan hole to top panel to allow it to intake
Cons - More modding of case, dust could enter PSU - not an issue short term but been thinking about the long term performance of the PSU, this is the main issue really, not too bothered about the modding side of it just possible dust build up and its effect

So basically I'm after opinions, with reasoning preferably, on whether it'd be best to mount it fan up (possible dust build up but cool) or fan down (no dust but will run warm)

Many Thanks in advance

[rafal_iB_PL]

Fan facing up is excellent for fanless mode, as you can freely take advantage of convection. And with lower intake temp, you'll stay fanless longer.

[ssshjp]

If I understand correctly, you are going to build water cooling and mount radiators on the bottom, right?

If yes, mounting PSU fan down should not increase the PSU temperature significantly.

[95thRifles]

Thanks for replies so far, just to clarify, this pic shows what I mean, rads are blu boxes at bottom and front, and PSU being the black box with outer red lining at top/rear

Both rads would be intaking air from fron/bottom and blowing warm air into case, so as you see the intake fan on the PSU can either be down, using the warm case air, or up, using the cool external air, but potentially gathering dust (over longterm)

Hope that clarifies



So you wouldnt envisgae any problems long term with dust build up inside the PSU?

[rafal_iB_PL]

Nah, you can always mount a dust filter at the top. Dust really isn't that big of a problem, unless you have a bit of OCD.

[ssshjp]

Got it. So the front fans would also blow warm air into the case.

A powerful rear fan may help protect the PSU from being hot with fan down. You can also use a magnetic dust filter for fan up, which is easy to remove and clean.

[mdk777]

If it is open at the top to let dust in: then you can see in right?
Once every six months to a year turn off and blow out dust with canned compressed air.

I too am offended by the disturbing grey fur that I see on/in my parents computers or sitting on office desks when I making sales calls....makes your skin crawl...but these 5-10 year old computers keep running anyway.

A little dust won't hurt, and a little air blows it out.