PSU at bottom of case?

[jaz2018]

I'm looking at buying a new case and am seeing PSU's mounted at the bottom directly (apparnently) underneath video cards or Ram .... this doesnt make sense to me -

Does anyone have any comments on this?

 

[13thmonkey]

i like a nice looking case, if I have to look at it every day I don't want it to look cheap. I will admit I have spent too much on cases in the last few PC but I wanted the one I have now since I saw it 5 years ago.

I saw a video about my case and it answered one question in my above answer... the reason no one does it is it makes no difference. The output of 3 x 180mm fans cancels out any gain you get from rotating motherboard 90 degrees, and blowing air out top. they just stood my case on its front and proved it for themselves.

I don't mind, its still a very good air cooling case. Beats most new cases into ground in that regard, just lacks a few newer features.

note: Raven RL02 & Fortress FT02 have the same internals, I have the fortress which is all aluminium and looks better than this one in video.

I do find the instant leaping to 'but heat rises!' as being important kind of funny. Yes it rises, so what, with the temps involved a vague draft would overcome it.

 

[Raiddinn]

You don't want heat from the video card and processor to go into the PSU, that's the problem with top mounting.

In the past when PC components didn't generate heat in meaningful amounts, it didn't matter if you top mounted a PSU and used the PSU as a case fan.

Once PC components started generating large amounts of heat, that became a problem.

See, PSUs work much much worse at high temps than they do at low temps and rising heat from components is a big deal. PCs with top mount PSUs often have a problem where they shut down during gaming but they work fine every other time. That largely is due to the heat generated when the video cards are actually working hard. That's why it only happens during gaming. The PSU fan is good enough during regular use and it just can't keep up with the heat generation from gaming.

PSUs that get too hot are much more also much more likely to have a critical failure event where they blow up and take something else (video cards or motherboards, usually) down with them.

You want to take the PSU completely out of that cycle and put it bottom mounted with the fan facing down. Then all it has to deal with is cold air in from the bottom and then it goes right out the back. It's unaffected by the heat of anything else, then.

Case fans need to worry about everything else and the PSU needs to only worry about itself. That's good design.

Also, another concern of note, you don't want the computer to be on the floor (especially if carpet). Putting computers on the floor roughly halves their expected lifespans. Much more dirt gets kicked up or vacuumed or something and sucked into PCs on the floor compared to PCs not on the floor. The PSU mounts that suck in air from under the case (ideal) also don't work when the computers are sitting on many floor types like carpet.