Bottom mounted PSU - what's the point?

A

AMD_Fan

Weaksauce
Joined
Jan 31, 2010
Messages
64
There's been a clear trend in cases the last few years to have the PSU mounted at the bottom. The advantages here seem to be that the AC cable is not gonna be hanging over all your other cables, and if you happen to have a non-modular PSU you can have the spare connections lay on the ground, and I guess it just makes more sense to have a massive power block lay on a firmer foundation at the bottom of the case.

But anyways, I digress, so the issue I have with this though, is for one thing the fan - cases with bottom mounted PSUs have a grill/dust filter at the bottom for the fan, but what is the point of that? So the PSU will be drawing in air from underneath the case (assuming you haven't put it on carpet and/or have a case that is sufficiently raised) and exhausting it right back out? It's solely for cooling the PSU, the rest of the case doesn't get any of that air intake. If it's at the top, the intake fan takes in all the hot air from the CPU/mobo and exhausts it thru the back of the PSU so that it becomes your main source of ventilation. Putting that grill at the bottom really seems like something case manufacturers have done so their case will be compatible with PSUs rather than for practical purposes.

Some people have said, flip the PSU over - okay, but first off that's just not how's its supposed to be mounted. In most instruction manuals it says mount it the correct way, and that's why those cases have that pointless grill at the bottom. It might work okay, but PSUs are designed with orientation in mind. Second, the intake fan is not really useful at the bottom of the case, hot air rises up, plus the bottom is farther away from the CPU. If it was an exhaust fan in that case it would be more useful but you can't really make it one. And finally, cables sometimes have a hard time reaching if you mount it at the bottom.

So maybe one solution here would be to have 2 different types of PSUs and you just buy the one that fits your case, or I don't know but at this point it seems dumb that PSUs are still made for top mounting and people have just started mounting them at the bottom. I have a Corsair 750HX, which is definitely better mounted at the top, so now I'm considering getting a new case, specifically looking at the 600T and it has the PSU at the bottom just like most other new good cases.

So what's your opinion/solution on this?
 
Last edited:
Cooling. PSU draws cool air from outside the case. Keeps PSU temps low and the fan from spinning up. On a cheap PSU, can also have a good impact on voltage stability, as temperatures inside a PC case are usually higher then ambient.
Most any case will have a dedicated exhaust fan...so the PSU is not critical with regards to cooling the rest of the components.

Secondary benefits are cable management and ease of instillation. Bottom mounted PSU makes a good deal of sense for many situations.
 
Bottom mounted PSU's also makes larger cases more stable by lowering the center of gravity.
 
DSee said:
Is it bad to mount the PSU with the fan facing up?
Click to expand...
Not bad, but if your case has a bottom intake vent and there is enough room below it for air to flow freely, it would be better to have the fan facing downwards.
 
It also frees up the top panel for exhaust fans which really help with airflow. Heat pooling is nearly nonexistent when you have air exhausting our the back and top of the case.
 
My PSU is mounted in the bottom of my case, a TJ07. My computer sits on my desk and IMO I would never set a computer on carpet. Hot air rises and cool air...you get the point. In my "case" I get cool air for the intake and the hot air goes out the side of the case.

Mounting a PSU in the top of the case should be OK as long as it vents to the top.

Just my 2 cents.
 
theseeker said:
Hot air rises and cool air...you get the point.
Click to expand...
That statement is only valid in a situation where there is no airflow. If there are fans blowing, the air will go wherever it's pushed, whether it is hot air or cold air.
 
I have a Cooler Master HAF X case which has the PSU mounted on the bottom. My response is in regard to the fan facing down now getting air circulation because of carpet. The HAF X comes with little wheels to put on the bottom which gives you good ground clearance so there's no problem at all with air flow.
 
You must log in or register to reply here.
Back
Top