Power Supply at the Bottom? why?

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slayer22
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Power Supply at the Bottom? why?

Post by slayer22 » Wed Sep 26, 2007 5:10 pm

hi i've been looking around and becoming familiar with cases and what i've notice is some cases have there power supply at the bottom? i was wondering why at the bottom my friend said it's cause these cases are S*** but i doub t it and i was wondering why..? out of curiousity to add on to my computer knowledge of a 16yo kid lol. he also said cases that don't come with powersupply are also s**t? and reason why?

here are som examples (its the pics that make me curious ;)
Image (antec p182)
Image(antec 900)

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Re: Power Supply at the Bottom? why?

Post by stev » Wed Sep 26, 2007 5:43 pm

It more of a thermal management issue with other benefits that became helpful.

According to the Intel and AMD Thermal Design Guides, the ATX form factor had a thermal achilles heel. The air coming in from the front bottom of the case would pass over many of the warm and hotter componts of the MOBO area and finally out the power supply (PSU).

As systems became faster, more heat was generated. As systems grew, so did the power requirements. Thus the PSU's were generating more heat themselves. Passing all of the internal heat from the computer through the PSU did not provide the thermal management capacity to happen well.

Intel tried to offer a new solution called the BTX form factor. After a few years, the BTX form factor really didn't get off of the ground. However, the "reconfiguration" ATX form factor of a visual footprint to the Intel BTX specification took off. Thus, the pictures you have posted.

Well, the front inlet air is now channel out directly to the PSU without adding any addition heat into the flow path. In turn front inlet air also passes over the MOBO and components to keep them cool too. Usually this "reconfigured" ATX style is in a larger case size offering more internal room for components and improved thermal air management.

Prior to Intel's BTX, Apple made the first splashes with this footprint from the G4 and G5 systems.

Personally, this layout is probally the best since it takes many other form factor queues and offers a great remix.
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Re: Power Supply at the Bottom? why?

Post by ibleet » Wed Sep 26, 2007 6:36 pm

My early Dell's like the Dimension 8250 had the PSU at the top, but my XPS Gen2 has the PSU at the bottom. It's just one of those things that I've noticed, but never put any thought into. I just figured it was about airflow and cooling.

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Re: Power Supply at the Bottom? why?

Post by Darkstar » Thu Sep 27, 2007 8:14 am

Cases that come without a PS are s*%^? no offense, but your friend sounds like an idiot. Whats his logic behind this? A lot of better cases come without the PS , thus allowing one to pick a (quality) PS of your own choice.

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Re: Power Supply at the Bottom? why?

Post by ibleet » Thu Sep 27, 2007 9:12 am

Darkstar wrote:Cases that come without a PS are s*%^? no offense, but your friend sounds like an idiot. Whats his logic behind this? A lot of better cases come without the PS , thus allowing one to pick a (quality) PS of your own choice.

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Some statements are just so "out there" that you have to ignore them. :lol:

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Re: Power Supply at the Bottom? why?

Post by dicecca112 » Thu Sep 27, 2007 9:23 am

yeah think you had an extra without in there DarkStar
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Re: Power Supply at the Bottom? why?

Post by Darkstar » Thu Sep 27, 2007 10:58 am

OK, lets change "without" to "dont come with"
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Re: Power Supply at the Bottom? why?

Post by slugbug » Thu Sep 27, 2007 11:12 am

The power supplies that come with most cases are cheap no name brands that I wouldn't trust to power my hardware with.

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Re: Power Supply at the Bottom? why?

Post by DMB2000uk » Thu Sep 27, 2007 6:04 pm

Specifically in the P182 you showed us, the PSU is placed at the bottom in a separate 'thermal chamber', which allows heat generated from the hard drives and the PSU to be kept separate to the main components, this allows both the PSU and main system to run cooler.

And PSU's that come in cases are not to be trusted. They are cheap and will not output anywhere near what they are rated at without blowing up.

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Re: Power Supply at the Bottom? why?

Post by slayer22 » Fri Sep 28, 2007 2:48 am

thank you guys for your answers now i can put up a fair arguement cause i was clueless why psu was at the bottom

well i had a further discussion with him and he said psu at the bottom gets dust really easily and i have not yet added your points but i will tomorrow thanks guys =D

he considers them s**t cause why shouldnt a case come with psu"

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Re: Power Supply at the Bottom? why?

Post by kenc51 » Fri Sep 28, 2007 8:24 am

The PSU at the bottom also helps distribute the weight in the case. When the PSU is at the top, the case can get "Top-Heavy" and it's easier to knock over.

Your PC will always get dusty, the positioning of the parts won't help. You just need to get a can of compressed air and clean it out evey now and then.

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Re: Power Supply at the Bottom? why?

Post by stinsonk » Fri Sep 28, 2007 4:58 pm

my friend said it's cause these cases are S***
Well the antec 900 is probably one of the most highly rated gaming cases available (that I know of, its been a while since I've had to build a high end gaming computer) and that antec is up there with it. As for cases without PSUs are s***...could you go and slap your friend for me (not hard of course, just a light smack :P) The reason cases dont have PSUs are cause so many different system needs are going into each case, theres no point in wasting money on adding in a stock PSU that will be swapped out anyways. This allows the user to choose a PSU based on your needs. As to why its at the bottom, I find that it makes cable management a lot neater *(personal preference of course) and can help with proper case airflow. If you imagine a case where all the air gets exhausted at the top back, its should go fine. But what happens when a bigger GFX card like the 8800GTX gets installed and traps air below it? It ends up building a area of static air that will be rather warm and start to overheat components (it WILL eventually get cycled, but its slower and will raise temps). Using a PSU at the bottom wthat has an exhaust fan will help to clear that air out and improove case cooling.

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Re: Power Supply at the Bottom? why?

Post by dicecca112 » Fri Sep 28, 2007 5:29 pm

The only issue I see with PSUs at the bottom is that hot air rises, and unless you have good design I can still see hot air accumulating in the top. But most cases with PSUs on the bottom tend to be well designed high end cases. Like my old Lian Li,it had that design and it cooled very well
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Re: Power Supply at the Bottom? why?

Post by stev » Fri Sep 28, 2007 6:18 pm

dicecca112 wrote:The only issue I see with PSUs at the bottom is that hot air rises, and unless you have good design I can still see hot air accumulating in the top. But most cases with PSUs on the bottom tend to be well designed high end cases. Like my old Lian Li,it had that design and it cooled very well

DMB2000UK stated, "... the PSU is placed at the bottom in a separate 'thermal chamber', which allows heat generated from the hard drives and the PSU to be kept separate to the main components, this allows both the PSU and main system to run cooler."

That should answer your statement of hot air rising inside of the computer. It really can not, as the chamber is designed to tunnel the heat outside of the case.
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Re: Power Supply at the Bottom? why?

Post by dicecca112 » Fri Sep 28, 2007 6:21 pm

I understand that, but I was thinking more if you just decided to take your standard el cheapo case and not have chambers and just keep the same open desing
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Re: Power Supply at the Bottom? why?

Post by slayer22 » Fri Sep 28, 2007 6:50 pm

he said u can use the stock psu for backup if the good one fails? i reasoned with him that good psu eg antec 550wats neopower would highly fail after about 3-5 years it should start failing like most psu's do(from my personal experience).

he also reasoned that the cables are too short to reach the components for example from the psu to the dvd drive located at the top if u know what i'm getting at =S




anywho i took my antec p180 back and got the p182 for a extra $10 lol
Last edited by slayer22 on Sat Sep 29, 2007 1:46 am, edited 3 times in total.

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Re: Power Supply at the Bottom? why?

Post by ibleet » Fri Sep 28, 2007 7:18 pm

LoL...I won't even dignify this nonsense with a response, its a waste of time. To each their own I say.

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Re: Power Supply at the Bottom? why?

Post by slayer22 » Sat Sep 29, 2007 1:04 am

well after i bought the p182 home i opened it and it was almost the same thing as p180 so i took it back and bought the antec 900 and i am completely satisfied! i love the 200mm fans the front and everything about it ..

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Re: Power Supply at the Bottom? why?

Post by stinsonk » Sat Sep 29, 2007 9:18 am

the PSU is placed at the bottom in a separate 'thermal chamber'
Actually in the antec 900, the PSU is in the same chamber as the rest of the system. expansion cards, however, can recreate chambers and allow for better cooling. This case has so much exhaust at the back and top that any rising heat from the PSU wouldnt matter anyways.

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Re: Power Supply at the Bottom? why?

Post by DMB2000uk » Sat Sep 29, 2007 9:49 am

I know that ^_^
DMB2000uk wrote:Specifically in the P182 you showed us, the PSU is placed at the bottom in a separate 'thermal chamber'
Quotes can take sentences out of context :P

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