Bottom Mount VS Top Mount

Is there any benefit to a bottom mount PSU? It seems this is becoming more popular since I left the scene in 2007... Mainly everything was Top Mount stuff. Just wondering...
19 answers Last reply
More about bottom mount mount
  1. If its bottom mounted you can have an extra fan at the top and the PSU is sucking in cold air from the bottom not warm case air. Also if you have alot of drives you don't need to run the cables as far.
  2. Bottom mount is better because it keeps the PSU cooler as it doesn't suck up the hot air within the cabinet.
  3. Ok, yea i noticed something has changed since most of the case's i see are bottom mounted. It seems reasonable to do things this way.
  4. The ATX case with a top-mounted PSU was designed in anticipation of that PSU being a part of its cooling; in a case with a bottom-mounted PSU, make sure you have at least one rear or top fan to exhaust heat.
    A bottom-mounted PSU with a 140mm fan can usually be turned either way. Fan-down, it draws cool air from beneath the case. Fan-up (or if it has an end-mounted 80mm fan), although it can help move air through the case it may not contribute as much to cooling because it is fighting physics (warm air rises). A front or side-mounted intake would probably be good to have if the PSU fan is facing up or is an end-mounted 80mm.
    Personally, I prefer the bottom-mounted designs because they also tend to be more stable, and cable management is typically easier.
  5. The issue I have with bottom-mounts is the location of the cables coming out of the PSU -- they are at the front opening as opposed to being at the back wall ...
  6. Yea I'm a huge fan of Lian Li... Had my PC-60 Lian Li since I think 2000?... built three builds, switched to an iMac... now i'm craving PC games again and I think it's time to build a new system.
  7. Anyway, I meant to Say I will be buying a newer age Lian li and I noticed alot of the mounts were bottoms.. ... WiseCrack, It seems that they come off the back of PSU and go right behind the motherboard and come in from behind... most of the pictures I seen, i didn't notice any obstructions with cables
  8. you can't turn that about face? so the fan is on the bottom and cables route towards board? that's odd...
  9. If there is a remedy I haven't found one -- if you are big on cable management (I'm obsessive about it) it can get annoying.

    I get by using a flexible conduit(s) and combining leads where I can - or by fabbing 'false' bottoms to cover it up (if you have a handy way of bending soft metal).
  10. the lian li cases i'm looking into seem to have well construction for neatness... and YES i am a neat freak. I can't stand a messy inside. That's why i was glad to see improvements on these modular PSU's.

    I been running an Imac for a few years now and i didn't have to work about noise, or a mess... but i am a windows guy at heart and i just miss gaming and tinkering with a PC so Im back! I'm gonna most likely build during Xmas... I wanna do atleast a few months of research since I been outta the game for awhile.

    I was considering building another AMD system, but the results of the 2500k,2600k CPU's look great.
  11. Rob423 said:
    you can't turn that about face? so the fan is on the bottom and cables route towards board? that's odd...

    Whether or not Wisecracker's case allows for it I don't know, but most cases with a bottom mount PSU are set up to have it in either orientation. Usually you can flip the PSU so that it pulls air in from beneath the case and expels it out the back. Flipping it also puts the cables towards the rear of the case.

    Edit: Corrected who I was referring to since I can't read!
  12. you mean if wise crackers case allows it?
  13. Probably not a good idea to flip the PSU upside down if it has a 'bottom-mounted' fan as above ...

    The SB procs are great -- but so are the x4 PhIIs (and Thubans). Hopefully they will bring BD along. Can't really make a bad decision these days on a new build (unless you try!) - get on eBlast and look for some deals.
  14. Wisecracker said:
    Probably not a good idea to flip the PSU upside down if it has a 'bottom-mounted' fan as above ...

    What do you mean by "bottom mounted fan"?

    Every PSU I've seen runs pretty much the same, the air is pulled in by the fan and pushed out the back of the case. So in the configuration above it is being used to pull air from the case and vent it out the back.

    Were you to flip it is would instead pull it's air from under the case which is better for PSU cooling since it's using cooler air.

    Though as has been said if you do this you need to add an extra fan to the back of the case to ensure proper air flow.
  15. A PSU does not care what orientation it is in for proper operation. Just make sure it gets airflow through it.
  16. Onus said:
    A PSU does not care what orientation it is in for proper operation. Just make sure it gets airflow through it.


    And 'flipping' the PSU above because of the fan orientation (I'll call that PSU fan above 'bottom-mounted') it looks as if air flow will be seriously restricted if you turn it over.

    That looks to be an Antec 900 case - if you try to flip the PSU over you will not be able to properly ventilate. Lian cases for the most part would work (they provide for ventilation on the bottom) but verify your mounting - and probably a good idea to install a filter.
  17. Cases without bottom vents will force you to install a PSU w/120mm fan like in that pic, which is upside down because the cable is away from the motherboard (you loose a good length for cable management) and the label is on the other side.
    These types of cases are made for PSU that have a 80mm exhaust fans such as this one.
    Anyone who has a PSU w/120mm fan and a case with no bottom vents may have to mod it themselves by cutting their own vents.
    Another is to buy a case that actually has vents on the bottom so those types of PSU can be installed in the correct position.
  18. it makes no difference which way the bottom PSU is facing. I've built systems in antec 300 and 900 cases that force you to install the PSU fan side up. I just use a filter to keep dust out of the PSU, that is the only issue. I've built in rosewill gaming cases where the PSU is top mounted, still had no issues with noise or heat.
    most current PSU have a long enough CPU power cable that you can run it behind the mobo from either bottom positions. right now I have two bottom mount PCs, one with the PSU fan up and one with it down. I have no issue with cable management, heat, or noise in either issue.

    I have noticed some PSU may have their fan spin faster when bottom mounted and fan down. As always, experimenting with your current set up will always get you better results then comparing against different set ups.
Ask a new question

Read More

Power Supplies Components Product