I am purchasing a new computer case for my system as my old case is too small for my new power supply, however, the case that I am leaning towards has the power supply mounts on the bottom of the case, and my current case has the mounts on the top. My Corsair supply has a large cooling fan on the bottom and it would not make much sense to mount it right side up on the bottom of a case. Just wondering if there is any risk of damage if I mount it upside down.
Definitely not a problem. Quite a few modern gaming cases are designed for power supplies mounted in the bottom rear of the case. You can safely install the power supply in the bottom of the case with the fan on top. It's not really upside down. Instead think of it as finally being right side up.
One idea behind the design concept is that a case with a heavy power supply mounted in the bottom is less likely to tip over than a case with a psu mounted at the top.
Another idea behind the design concept is that by moving the psu to the bottom of the case there is room for an exhaust fan at the rear of the top panel which could help to exhaust warm air.
A third idea behind the design concept is that the psu fan which pulls in warm interior air and exhausts out the rear panel can help cool the video card which is installed just above it.
Thanks to everyone that replied, I had figured it wouldn't be a problem. I purchased an Antec 900 case. Should be large enough to handle my Corsair TX750, which has too many wires to hide in my old case resulting in it being jerry-rigged behind my case - resulting in obvious dust issues.
I have been in the process of completely re-doing my computer which I bought as a pre-assembled computer 3 years ago before I discovered the wonders of building my own computer. I started by upgrading my video card to an ATI Radeon HD4850, which I bought before foolishly realizing it required more power than my current psu could supply. Now that I'll have a case to fit everything in, I begin the search for a new CPU & Motherboard, as. Pretty happy with the direction my system is going.
I'd be a little reluctant to claim that one of the key features of puting a PSU at the bottom is to act as an exhaust for the graphics card. Because a PSU is one of those parts that you don't want to overheat, it would be a poor choice for an exhaust port, although I don't deny that it does exhaust some of the air in a case. That being said, since heat rises, I don't think a PSU at the bottom of the case is in any danger of overheating even if it were closer to the GPU. In fact, I believe puting the PSU at the bottom of the case will keep it colder because it's not required to exhaust the warmer air on top of the case, increasing efficiency and long-term stability of the system. You are right to say that it leaves room for serious exhaust where it's needed most - at the top-rear of the case.
All modern power supplies pull in air and exhaust air out the back.
With the older cases with top mounted power supplies, they pulled in warm air from the cpu area and exhausted it out the rear panel. With the psu mounted in the bottom it simply changes location. It still pulls in warm air from the interior and blows it out the back. On most modern high quality power supplies the fans are temperature controlled. If temperatures increase the fan speed increases. I had to laugh when the Corsair HX620 came out a few years ago. PC's were sitting at idle and people were complaining the fan wasn't working. The didn't know about the temperature controlled fan and didn't realise what a heavy duty, high quality unit it was.
It's pretty normal for gpu temperatures to be higher than cpu temperatures. I'm also not too crazy about the design of fan shrouds on video cards. I have yet to see one that could efficiently exhaust hot air. Mostly they just blow hot air inside the case.
I actually think there is much merit in this design to a point I don't think I would ever want to go back to the conventional top PSU design. With the PSU on top if you touch the immediate area over the PSU you will notice that it is slightly hot. I was of the opinion that this heat was mostly from the PSU. Now with the PSU on the bottom of my new case, I touch the same top back area of the case and still notice that it is hot. This time because the 120MM fan mounted just is below blowing hot air out. Now think about your expensive and shinny new PSU and think of that hot air from the case blowing through it. In actuality modern PSU's are designed only to cool themselves. Never were they intended to be use as a cooling solution at large. Just a simple observation of the RPM of a modern PSU fan is a clue that it has little benefit towards cooling the case with todays high performance components. My current case (Gigabyte Luxo M1004) has a air intake at the bottom of the case and I have my PSU installed in such a way that it sucks outside air from the bottom of the case and vents it out the back. I think bottom PSU mounted case design helps extend the life of both the PSU and components.
In the original atx standards developed by Intel, the specification called for the power supply to be located near the cpu. The reason for that was Intel developed new cpu's that were running hotter. The psu had the only fan that could exhaust hot air from the case. Back then cpu's and cases did not have any fans. That was a long time ago. Things have changed quite a bit.