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Oscar40

Upside down power!

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It never ceases to amaze me the amount of power supplys that are fitted to the bottom of the case with the fan intake ftat on the bottom,yes even on these pages,I just happened to have the side panel off my pc yesterday ,it was built by one of Perth's largest outlets,and I was "gobsmacked" to see the power supply thus fitted! just a few minutes with a screw driver to change it,yes there was plenty of cable slack and the case had screw holes for both ways,so why!!! Doc

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Damm you hitman I was trying to fix this post and you buggered it up :P

Edited by bowiee

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why!!! Doc

Because they don't care, its that simple. Oh and by the way if I were you I would build your next computer yourself, its not hard and there is plenty of top quality help in these very forums. :)

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why!!! Doc

Oh and by the way if I were you I would build your next computer yourself, its not hard and there is plenty of top quality help in these very forums. :)

 

This, if you can turn a PSU around you can build a computer.

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why!!! Doc

Oh and by the way if I were you I would build your next computer yourself, its not hard and there is plenty of top quality help in these very forums. :)

 

This, if you can turn a PSU around you can build a computer.

 

maybe it was a work computer?

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Thanks everyone for commenting,and yes i've built plenty of computers before,since 286 days actually,but this one was an xmas present from my wife!

And no it was a full on games machine that I would have expected the builders to take reasonable care with,never mind,I only posted it awareness sake! Doc.

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As above, they most likely installed it without thinking. Only possibility would be that the PSU intakes slightly cooler air from the bottom of the case, but that's outbalanced by being potentially starved for air.

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What kind of case is this as I can't understand how this is fail.

 

Every case I've worked on has had a vent on the bottom usually with a fan filter to stop the dust bunnys. The only problem is placement, don't put those case's on thick carpet and keep the bottom of these case's clear. Doesn't seem hard to me.

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What kind of case is this as I can't understand how this is fail.

 

Every case I've worked on has had a vent on the bottom usually with a fan filter to stop the dust bunnys. The only problem is placement, don't put those case's on thick carpet and keep the bottom of these case's clear. Doesn't seem hard to me.

Funny the only cases I have worked with do not have any vents of any kind in the floor of the case. It was a fail to the OP as his case, like all the ones I have seen and use for clients, had a solid floor. So the fan was facing solid metal. Edited by bowiee

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What kind of case is this as I can't understand how this is fail.

 

Every case I've worked on has had a vent on the bottom usually with a fan filter to stop the dust bunnys. The only problem is placement, don't put those case's on thick carpet and keep the bottom of these case's clear. Doesn't seem hard to me.

Looks like I should have spelt it all out,:-) NO there is no hole /vent of ANY kind in the bottom of the case,its an "ANTEK 900 two V3",and the power supply is/was mounted flush with the bottom,ie NO possibility of any air to the fan!

Its now happily sucking air from inside the case and blowing it out the back like it should. As I said you would have to be a bit thick to install one like this! Hope that clears it up !

 

What kind of case is this as I can't understand how this is fail.

 

Every case I've worked on has had a vent on the bottom usually with a fan filter to stop the dust bunnys. The only problem is placement, don't put those case's on thick carpet and keep the bottom of these case's clear. Doesn't seem hard to me.

Funny the only cases I have worked with do not have any vents of any kind in the floor of the case. It was a fail to the OP as his case, like all the ones I have seen and use for clients, had a solid floor. So the fan was facing solid metal.

 

Yes,spot-on Bowie! Doc.

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Mine has air vents in the bottom of the case... and the power supply is slightly raised above the bottom of the case...

 

 

 

 

 

 

Just sayin' ;)

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Mine has air vents in the bottom of the case... and the power supply is slightly raised above the bottom of the case...

 

 

 

 

 

 

Just sayin' ;)

Which case do you have ?

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As Caelum points out, well designed cases put the PSU at the bottom and provide appropriate vents. The idea behind it is to not have hot air from the case going through the PSU, making the PSU operate hotter and need more/louder/better fans.

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Fractal Design R3:

 

http://images.bit-tech.net/content_images/...sign-R3-5-l.jpg

 

 

 

The PSU isn't quite right on the bottom of the case... and as you can see, there's ventilation holes there too... There's also another fan slot forward of the PSU, but still on the bottom.

Sweet, I have never used Fractal (never had a close look as their range is small) which is why I have not seen the vent in the bottom of the case before I guess. But I am sure others will include it eventually, and I notice that those particular Fractals are reasonably priced. :)

 

Hmm I especially like the look of the ARC Midi Tower at only $128.00 from umart it looks like a great budget case, and has the front USB ports in a handy top mounted position. :)

Edited by bowiee

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shrugs.

I got a nice big hole in the bottom of my case, designed just with the PSU in mind - every case I've had has had adequate ventilation for the PSU, ever since the 'good old days' when they used to be mounted at the top of the case.

never had the problem.

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I've got an old faithful original CM690, and it has a nice hole cut in the bottom for the PSU to take in fresh air. I thought most cases were this way? Wasn't that the whole reason behind modern cases moving the PSU from the top to the bottom of the case?

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Most of this is ametuer and incorrect advice. The OP has no understanding of how his Antec Nine Hundred works and is being steered wrong.

 

So has anyone here ever seen a quality PSU or PSU fan give out because it overheated or was overworked from air starvation from being on the bottom, face down, with no case holes under it? Of course you haven't. We've yet to see one of our builds mounted on the bottom fail for any reason, but we've used Corsair PSUs exclusively for the last 3 years or so too. I've rarely seen a quality PSU fail on negative pressure systems (which we didn't build). That's the only way a quality bottom mounted PSU should fail, and won't matter if it's facing up or down.

 

I'll disagree with all of these posts claiming that good cases put holes on the bottom. It's just another dust cover to clean, not nearly as effective at keeping dust out of the PSU as a case with no bottom PSU holes no matter how good the filters are, and causes more air starvation than a correctly built positive pressure system.

 

Think about it. Cases with holes on the bottom often have the PSU sitting directly on the floor and force them to suck air through a filter rather than via positive air pressure in the case. Talk about air starvation? I pretty much guarantee that if you test the air flow through the PSU on a dirty filter on the bottom, vs pointed down with no holes on an Antec witch includes a gap for air feed on a positive pressure system with dirty filters or turning it upside down on a positive pressure system with dirty filters... you'll find there is better circulation through the PSU on a positive pressure system on any given case model than one forced to suck directly through a filter.

 

Caulem is correct for the reason of the bottom being cooler air than at the top or middle of the case (and it's measurable with proper air flow). Caulem is dead wrong about a case with holes and filters on the bottom being a better design. They're a gimmick.

 

I haven't used a Fractal case either, but I've used others with similar designs (holes and filters on the bottom) and even beefed up the filters with 1/2" foam rubber to cut down on the dust because it's a stupid design for systems in a dirty environment or that must sit on a carpet. The PSU still get's dustier with this design than one without holes on the bottom. Not really a big problem as I've rarely seen a quality PSU fail on the bottom, but not a better design in any way. Again, those bottom holes and additional filters to clean are nothing but a gimmick and do nothing to prolong the life of a PSU. They cause more air starvation than a correctly setup system with positive air pressure.

 

Both my wife and I are currently using Antec twelve hundred(s) with no hole on the bottom. We've built about 300 systems with Antec Three Hundred cases for customers, and roughly the same amount with Antec Nine Hundreds, all with Corsair PSUs. Some of these are sitting in extremely dusty factory environments and the PSU is still fairly clean, though the filters tend to build up 1/2" of dust and require the CPU fan to be cleaned every few weeks. I recommend adding a 1/4" foam rubber filter in front of the side fan, which is quite effective at stopping dust and still allows good air flow from the 140mm fan (we use CoolerMaster 140/120mm Silent Fans with good luck).

 

All of these Antec cases supply at least 1 foot under the PSU at the front and the mount at the back is on a lip so that the PSU cannot be on the floor of the case. This is a win/win in a positive pressure case as it's fed cooler air from the bottom of the case via the side door fan and back vents behind the PSU which go to the area in back between the wiring space and door, and keeping dust to a minimum because big dust bunnies can't fit under the PSU. The side door fan streams directly to the GPU (which is caught up in the front stream and exhausted out the back) and to the PSU, while the front fans streams widely over the motherboard and out the top and back of the case. This is the best case design for a PSU mount, period. Our PSUs are almost perfectly clean after the case sits on a plush carpeted floor for months at a time between cleanings. That's how to build a case properly with the PSU on the bottom, intake facing down, as all dust buildup goes up to the CPU or out the back/top of the system. The CPU cooler is a different story, and is the reason that these systems can't be cleaned less often or not at all (although I'm pretty anal about keeping my system clean and checking it over every 3 months or so).

 

If you think there's no air flow in your Nine Hundred from the PSU facing the bottom, then how would you explain the air coming out the back of the PSU? It can't blow out what it can't suck in. Do a smoke test with your favourite smoking material to check the air flow both ways. Bombard it with smoke - from your bong if that's your thing. Did you notice any difference when turning it upside down in air flow coming out the back? I already know the answer - there is no difference. The PSU will get slightly dirtier being put upside down, and that's the only difference (other than also being fugly and looking like it was built by an ametuer). If you run a lit cigarette all the way around the PSU bottom you'll see it sucking the smoke from every angle, and on these Antecs there's much more than the required space for air flow at the bottom. If you supply enough smoke, you'll see some float up as there's more air in the system than the PSU needs, and this will be the same whether it's facing upward or downward.

 

The amount of air sucked through a PSU by even the biggest fan isn't more than needed from a couple thousands of an inch clearance.

 

Doesn't appy to OP's current situation but if your case has no feet under the PSU mount, any decent PSU still has a grill and grill screws on the bottom which the PSU will sit on, and again have plenty of air flow. Some PSU manufacturers design the grills intentionally curved enough to stand out further than the screw heads, to sit on the grill on cheap cases and be fed or suck air from around their sides in all directions. Some design the screw heads to the grill to be sitting on the bottom of a cheap case. Do you think manufacturers would design their expensive PSUs to fail, knowing they could be mounted in a cheap case facing down? They understand what is required for air flow and build accordingly.

 

You should also have positive pressure inside the case (meaning more fans going in than out - and don't forget to consider the PSU fan going out) to have correct air flow. Make sure your builder wasn't a knob and put enough intake fans in, or add some more on your own. Facing up or down, in a positive pressure case the PSU fan will be fed more air than it can handle, not be starving for air. This science is about a century old. We're not talking water here. Air travels quite easily between the smallest of cracks. In fact, with a smoke test on a correctly built positive pressure system you'll be amazed at how many leaks every computer case has to allow air to flow out. If the air is circulating rather than streaming, you have a crappy case design. These Antecs have a very good air flow system which streams well from front to rear and top (with enough fans) and from the side to the bottom and middle exhausts.

 

Air for the PSU on these Antecs gets streamed straight from the side vent fans (if you place one there) which is cooler since it doesn't travel the length of the case and is situated at about 1/3 or less from the bottom of the case. Only if there are no side vents does the air get fed into a bottom mounted PSU from the case front. It will still be cooler air than what is streaming to the middle or top of the case unless you have a dinosaur case that doesn't have good air flow anyway. Again, a smoke test will show you exactly how the air is circulating incorrectly or streaming correctly in your case.

 

The only exception would be if you're using a cheap generic case with no lip or feet and a generic PSU with the intake at the front of the PSU, and that's easily remedied too. There's a bit of play with the PSU screw holes to allow the PSU to be a few millimeters off the floor. If building yourself or adjusting a shitty build from some manufacturer, simply loosen the PSU screws and slide it up as far as you can - place match book covers (0.016" thick) under both sides of the PSU, and retighten the back screws (don't forget to pull the matchbooks out when you're done). That supplies more than enough space for air flow around the PSU (also worked perfectly for gapping the points on my '69 Chrysler 389 Police Interceptor, but that's another story). You can even use the lip of a cardboard box (thicker, but accomplishes the same thing to get the PSU off the case bottom). You don't want a flat side of the PSU on the flat floor of a case, but it only takes a couple thousands of an inch to create enough air flow for a generic PSU (which will likely die for other reasons anyway).

 

At any rate, there is no starvation of air unless you put a gasket or silicon around the bottom of the PSU on an Antec Nine Hundred.

 

These Antec cases have some disadvantages (IE: the front filters are a bitch to clean as the side(s) have to be taken off to remove the screws holding each bay, and hot hard drives are mounted right in front of the front fans causing hot air to be streamed across the motherboard), but the PSU setup is state of the art and among the best on the market. These cases are designed to have the PSU mounted downward for a reason. The science has already been done for you. If you don't trust the research put into these PSU and case designs, by all means buy the gimmicks to satisfy your ignorance. Antec has been a case leader for decades for good reason. If you actually test the air flow on your systems, you'll see what is good and what is just gimmicks. Then you won't find yourself posting incorrect information to others as well. :-)

 

[Looks like I should have spelt it all out,:-) NO there is no hole /vent of ANY kind in the bottom of the case,its an "ANTEK 900 two V3",and the power supply is/was mounted flush with the bottom,ie NO possibility of any air to the fan!

Its now happily sucking air from inside the case and blowing it out the back like it should. As I said you would have to be a bit thick to install one like this! Hope that clears it up !

BS. If you look at the Antec 900 2 V3 it has feet and a channel underneath for air to be fed via positive pressure in the case. If you have enough intake fans, it's not sucking anything - rather it's being fed air via positive pressure.

 

I don't think you should be building systems if you don't understand this setup and can't even see that it wasn't sitting flush on the bottom of the case at the fan. That case is actually a very good design for the PSU to be mounted downward. :-)

Edited by darklife41

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I fully agree, install the bits into the case in the way the manufacturer recommends, thus taking into consideration all their design decisions.

 

From the manual on the case in question :

 

Note: Power supplies will need to be mounted so that the PSU fan is facing the top of the case. Nine Hundred Two V3 provides mounting holes for power supplies with standard mounting layouts to be installed upside up or upside down.

 

I probably wouldn't buy from a PC builder who goes against manufacturer recommendations.

Edited by Mac Dude

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From the manual on the case in question :

 

Note: Power supplies will need to be mounted so that the PSU fan is facing the top of the case. Nine Hundred Two V3 provides mounting holes for power supplies with standard mounting layouts to be installed upside up or upside down.

Just in case he doesn't believe you, here is the manual:

http://www.antec.com/pdf/manuals/Nine%20Hu...20Manual_EN.pdf

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You know you could of explained that in about one paragraph.

You couldn't possibly fit that much smug in one paragraph!

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I have my fan facing the top of the case and very rarely overheats. But i did find on one occasion that the sticker from the GPU fell down on the PSU and it was blocking it and started to get warm ,this happened in Winter and did not notice it. Must have been in September when i noticed it and removed the GPU Sticker from the Fan.

 

SO why do they put Holes Facing down in the bottom of the case ? This is probably why so many mount their PSU facing the bottom.

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