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January 2, 2007 10:19:44 PM

I want to get this PSU: Corsair HX520w: http://www.jonnyguru.com/PSU/HX520W/

and

this case: Antec Nine Hundred Ultimate Gaming case: http://www.overclockers.co.uk/showproduct.php?prodid=CA...


I have noticed that this case is unique in the sense that the PSU mounts at the bottom. Now thats all well and good apart from this type of PSU has a fan on its bottom. Surely in that case, the PSU will "explode" after a while as all the heat gets trapped in, etc. I'm pretty new to building my own PC but I'm guessing most PSU's either have no bottom-fan or Antec is being a bit silly with this case. I dunno.

But it should be easy for me to fit the PSU up-side down right? Thats not going to damage the PSU or anything like that is it?

Cheers for any insight. (I'm prob just being crazy).

More about : check

January 2, 2007 10:22:09 PM

Im pretty sure that's how you mount the PSU (with the fan facing up for bottom fanned PSUs). It will not damage the PSU by simply mounting it upside down or as many people wouldn't buy the Antec 900 :o  !
January 2, 2007 10:23:12 PM

Quote:
(I'm prob just being crazy).


This is a good thing when building a computer :D  .
Related resources
January 2, 2007 10:45:22 PM

Actually screw it. I'll get a Antec Super LanBoy. My mate has it and it seems to keep his rig cool. http://www.antec.com/us/productDetails.php?ProdID=15001...

I just read this thread: http://forumz.tomshardware.com/hardware/Antec-Hundred-A... and it has put me off the 900 a little. I don't want a bottom mounted PSU, or wires stretching all over the place to find the Mobo, etc. I just want something I can put a system inside without any trouble and which does not get to hot :p  The LanBoy may do just that... unless there are any horror stories I haven't read about it :?

Plus its about £20 cheaper and I'm a cheap bastard.

It would be comforting if people put their views about this case, whether good or bad (and hopefully from experience), to help me make up my mind =)
January 3, 2007 2:53:44 AM

[tongue-in-cheek mode= on]

You can't mount the power supply upside down, the electrons will leak out of the capacitors.

[/tongue-in-cheek mode]

Power supplies are physically pretty rugged and will work in any orientation, upside down or sideways. I have had experience with both top and bottom-mount cases. Frankly it was more difficult to work with when putting the pc together using the bottom mount, but in the end it worked out ok. As far as the intent on keeping the power supply heat away from the motheboard heat, I don't have any qualitative data on that.
January 3, 2007 6:24:26 AM

Quote:
[tongue-in-cheek mode= on]

You can't mount the power supply upside down, the electrons will leak out of the capacitors.

[/tongue-in-cheek mode]

Power supplies are physically pretty rugged and will work in any orientation, upside down or sideways. I have had experience with both top and bottom-mount cases. Frankly it was more difficult to work with when putting the pc together using the bottom mount, but in the end it worked out ok. As far as the intent on keeping the power supply heat away from the motheboard heat, I don't have any qualitative data on that.


PSUs are more fragile than HDDs! :lol:  I think I'd like to measure the ambient heat in my case once I get my build up and running and overclocked. Is there a tool where I can sample a certain area's temperature? As long as it's not too expensive maybe I would check one out.
January 3, 2007 4:56:00 PM

Yes, there are thermocouple wires you can insert into your power supply. There are also two-part epoxies that you can use to temporarily glue a thermocouple to a part or heatsink. It is quite dangerous for an inexperienced person to try, though, because you can't tell by looking unless you already know, what the high voltage parts are and what the low voltage parts are.

There are other factors as well. For example, the transformer may get as hot as 60C without any problem. You may not know how how certain areas of the power supply may be yet not have an issue because they were designed with to handle that amount of waste heat. Think about this: if you have a 1000 watt supply that is 80% efficient, then there are 200 watts of energy lost as heat inside that power supply. Think about 200 watts for a minute, say like how hot a toaster can get or a hot air gun at 200 watts. For reading the temperatures there are plenty of low cost meters that can take a thermocouple input directly.

In many power supplies the heatsinks are hot electrically, meaning that they carry hot voltages on them. If you have more than one thermocouple in the supply, they may be at very different voltages. Those wires normally can't be connected to the meter at the same time for it will destroy the meter. The other very big risk is when you install the thermocouple, the heat may cause the thermocouple to pop off where you glued it or simply curled up a bit and shorts something out. There are parts inside the power supply that will give off a large bang if accidentally shorted. Remember you have mains voltages coming into the supply and they are inside there at a lot of different points. Even in the low voltage sections, accidentally touching a pin on a chip could cause the control to blow up the supply.

Better would be an indirect measurement. You can measure the temperature of the air at the inlet of the supply and measure the temperature at the exit of the supply. Do the math and you have a temperature difference. That difference can be calculated in watts. The problem there is finding the math for those calculations and doing them correctly.

There are people, however, who go in, with some knowledge and are successful at modding even a power supply. If its just curiosity you have to know how hot it gets in the power supply, you may get results you don't understand anyway.
January 3, 2007 5:14:54 PM

DOn't get the SuperLanboy, i've got one, yeah it does keep everything cool but its a small case, i struggle to get a 7900GTO in, i seriously doubt that any dx10 cards will go in if they're anything like the 8800GTX, and theres already rumours that the r600 will be the largest (and hottest, and fastest) card ever.

The Nine Hundred looks great though, and i've heard that it fits 8800GTX in SLI so i'm getting one when i get paid next. You might want to think of changing your PSU to a more accomodating one if you're not too settled on your decision
January 3, 2007 5:44:23 PM

What ever happened to Lego Cases???? They are expandable, as large as you need them to be, as efficient as your engineering skills, and very stylish... and cheap if you got them already.
January 3, 2007 5:59:10 PM

What you say is true. Hmm. I guess I can still get the Nine Hundred. Everyone has told me that PSUs are robust so I'll just put that upside down. Its a Corsair HX520w so its modular and I think that means I can detach unused cables, etc, so my case won't be too messy. Plus I'm hoping it has long cables to travel all the way up the case.

The P5W DH should be fine right?

Cheers for any info =)
January 3, 2007 9:43:18 PM

I haven't heard any horror stories about upside down PSU's and there are a few VERY popular cases with bottom mount PSUs. Also a couple that mount the PSU sideways that have some popularity.

With some time, wire routing (for me) is actually easier with bottom mount PSUs because gravity helps 'fasten' your wires to the floor of the case :)  No need for a zip tie anchor or anything like that to hold wires to the roof, just bundle them with a zip tie or twist tie from some bread and tuck the extra length behind the HDD cage or wherever you want.
January 4, 2007 8:54:52 AM

why fight the laws of physics? heat rises and should be evacuated from the top of the case. i learned that principle 30+ years ago in my heat & thermo physics course in college. if the PS is mounted at the bottom, you are trying to suck the heat down contrary to it's normal flow. i would never buy a case with the PS at the bottom out of simple logic.

also with the PS at the bottom, heat will tend to be trapped around the mother board, plug-in cards, and disk drives above it. this could cook the system very quickly.

as my mother said to me many times, "use your head for something other than a hat rack!" bobvc99
January 4, 2007 1:02:28 PM

heat doesn't always rise. It depends on the surrounding air density.
--> What he could do is buy the case, then use it upside down.... this would put the PSU back at the top....

Or suck enough air from the bottom to create a negative density grade which will cause the hot air to sink instead.
January 4, 2007 4:47:27 PM

You should actually check out the reasoning and engineering that goes into the bottom mount cases. The bottom area is isolated from the top area. Heat there is exhausted to the rear of the case. Only a small portion of the heat produced by the power supply will be radiated and convected through the divider and through the holes where the wires come up. Another principle is that the supply air to the power supply comes from the front of the case and is cool, allowing the power supply to run cooler. Putting the power supply at the top means warm air is going into the supply, increasing it's internal temperature.

In theory you are right. In practise you don't have a clue.
January 4, 2007 5:08:49 PM

Your statement is assuming that the PSU generates a positive amount of heat inside the case. (meaning it creates more heat then it removes with the large fan).
January 4, 2007 6:04:18 PM

I am not assuming anything. Ever touch the case of the power supply inside your computer? That heat you feel is being radiated into the space inside. As far as the bottom mount power supply the point which I may have not made clear is that the power supply input air is pulled from the front of the case and not from the top of the case so cool air goes into cooling the power supply. In the top mount power supply the air pulled into the supply is already heated air.

Facts: the power supply generates heat and also has an exhaust fan or two inside it.

On the motherboard the processor and chips generate heat along with the graphics card. A fan on the processor heatsink blows air that is in the case through the fins.

A case has at least one fan exhausting air out the rear of the case and pulling air in from the front.

Separating the power supply by bottom mounting it in a separate enclosure removes much of the heat load from the motherboard, hard drives and graphics card that would be pulled through the power supply. In addition most of the heat generated by the power supply, rather than being radiated into the same space as the motherboard, is exhausted out the rear of the case.

It might help if you looked at the case in detail to understand what I am saying.
January 4, 2007 6:14:06 PM

The powersupply will continue to radiate heat by convention into the main body of the case. (heating up the compartment, heating up the metal, heat warms the air inside the case.... im sure you know this just saying..)




What I was saying is (which you didnt mention):

IF the PSU removes more heat from the case then it creates, via 140mm fan, then its doing good.... if its adding to the eternal heat (not happening), then its not doing any good.


So it depends on the PSU you are using whether or not seperating the psu more beneficial or not.
January 4, 2007 6:26:19 PM

===============
-...............................=
-...............................=
-...............................=
-...............................=
-...............................=
-...............................=
-...............................= Air heats up from hot metal.. rises from the bottom.
=------------------------- --> metal divider heats up
-...............................=
-...............PSU..........= --> exhaust fan
-...............................=
=======-----------==
U|U.................|---> psu exhaust



I haven't seen the specific case, but if it has a top exhaust fan, thats all it needs.

Boy that image was bad lol
January 4, 2007 8:17:33 PM

Comptia rep:

i agree with you about needing the top exhaust fan in ANY case.

------------------------

everyone here has made some valid points but, inside a closed computer case the rule stands, HEAT RISES! air density is of no effect unless you are speaking in terms of the macro world around each individual component.

if you mount the PS low and make sure there is a proper size fan near the top of the case and adequate air intake near the bottom, i can't find fault with anyone. with the additional exhaust fan mounted high in the case, you would not be relying on just the PS exhaust fan to remove heat.

when i said i would never buy a case with the PS mounted low, i was referring to a system where the PS fan was the main or only heat exhaust. i generally don't add 3 or 4 fans to a desktop computer case. :) 
January 4, 2007 8:22:30 PM

If lets say, the intake fans were blowing in air of much lower density then the existing air inside the case, the hot air would sink instead of rise.



Likewise, if you were to release highly compressed air into the case, ... things would freeze instantly.
January 4, 2007 8:47:10 PM

Quote:
The powersupply will continue to radiate heat by convention into the main body of the case. (heating up the compartment, heating up the metal, heat warms the air inside the case.... im sure you know this just saying..)




What I was saying is (which you didnt mention):

IF the PSU removes more heat from the case then it creates, via 140mm fan, then its doing good.... if its adding to the eternal heat (not happening), then its not doing any good.


So it depends on the PSU you are using whether or not seperating the psu more beneficial or not.


Try this: on a bench setup have your power supply off to one side. Now it's only sucking room air through it. Does the case of the power supply still get warm? The answer is yes. So does the fan remove more heat than the supply produces? the answer is no, for if it was yes, then outside the case the power supply should get cooler in time if the fan inside is blowing heat out faster than the power supply can produce it!
January 4, 2007 8:58:13 PM

no... you are wrong, but most likely I just explained badly. When I have more time I will reply.
January 4, 2007 9:47:26 PM

I am not wrong. If the heat removed by the fan is at a rate greater than heat produced then the box should be at room temperature and all the heat produced should be expelled from the exhaust vents.

Question: why does heat rise? Answer: gravity.

BTW, in fluid dynamics explain what happens when you have a strong flow of fluid into a box that is of one temperature and the static fluid in the box is at another and is disturbed by the flow?

If you are going to prove me wrong, you had better produce the math.
January 4, 2007 10:00:26 PM

2 minutes left to respond before I go home.


I dont need math to show you what I am talking about.
and yes... heat rises because it is less dense, not because of gravity. Hot air on the ground doesn't rise if the air above it is the same temperature.


Ok done... will reply again.
January 4, 2007 10:23:47 PM

Quote:
2 minutes left to respond before I go home.


I dont need math to show you what I am talking about.
and yes... heat rises because it is less dense, not because of gravity. Hot air on the ground doesn't rise if the air above it is the same temperature.


Ok done... will reply again.


In micro gravity experiments it is proven that gravity is the reason heat rises. What you are talking about is heated air rising. Radiated heat also rises, but it's because of gravity. In a micro gravity environment heat actually radiates in every direction and hot air expands in a spherical shape. The light of a candle is a sphere rather than the tear drop shape caused by the rising of gas. By the way, air density is caused by gravity.
January 4, 2007 11:15:11 PM

Quote:
In micro gravity experiments it is proven that gravity is the reason heat rises


??? How would heat rise BECAUSE of gravity? Did you mean the lack of gravity?
January 4, 2007 11:15:34 PM

I believe the idea of putting the power supply at he bottom is a fairly sound idea

funny guys on here, quibbling about heat rising...

meanwhile on bazaro world heat stops rising due to negative gravtity.. personally i think the arguement they are having is going the wrong direction

yes the power supply is at the bottom, but they have tried to isolate it with a shield, dunno how well this truly works, thought i saw a couple articles that stated the over all case temps did indeed drop

but at what cost? more fans to isolate diff areas? its not a big deal to me - hell i love fans and noise.... is it a big deal to you?

i dunno crap about the actual design other than how it looks, hopefully some one can give you a few links and some more insight ...

you other guys ..... one of you is goading the other one a bit to much, try to contribute to the mans post a bit....
January 4, 2007 11:39:34 PM

Quote:
I believe the idea of putting the power supply at he bottom is a fairly sound idea

funny guys on here, quibbling about heat rising...

meanwhile on bazaro world heat stops rising due to negative gravtity.. personally i think the arguement they are having is going the wrong direction

yes the power supply is at the bottom, but they have tried to isolate it with a shield, dunno how well this truly works, thought i saw a couple articles that stated the over all case temps did indeed drop

but at what cost? more fans to isolate diff areas? its not a big deal to me - hell i love fans and noise.... is it a big deal to you?

i dunno crap about the actual design other than how it looks, hopefully some one can give you a few links and some more insight ...

you other guys ..... one of you is goading the other one a bit to much, try to contribute to the mans post a bit....


i believe the antec 900 has enough fans that heat isnt a factor.
January 5, 2007 12:45:33 AM

I thought the heated gas moved to one side or another in zero gravity (in a box).... Separating the densities, not merely one existing within the other.
January 5, 2007 1:32:16 AM

Quote:
I thought the heated gas moved to one side or another in zero gravity (in a box).... Separating the densities, not merely one existing within the other.


Gasses diffuse until the concentration is even throughout the enclosure.

One thing one keep in mind though, is that you move air with fans, so blow hard enough and I don't care how hot the air is, it will move in the direction of air flow, even if that is straight down. So heat rising is for still air.

Now how gravity plays a role: due to gravity the density of air increases as it gets closer to the surface. Air heated will rise, simply because it is lighter, just like helium and hydrogen will rise. Now, in space, this doesn't happen since there is no pressure gradient, it's a microgravity after all, so simple diffusion occurs through Boyle's law. In the space station, though, there are air currents caused by the ventilators, so even there diffusion doesn't follow still-air rules.
January 5, 2007 1:52:57 AM

Well now im only 1/2 thinking tonight rofl. Stupid synthahol.,... :) 


Anyway, I know the density will continue to seek equilibrium... but instantaneously.



anyway.... i relinquish my opinion here....

PUt a 120mm fan on top of the case, and be done with this convo.
January 5, 2007 2:13:34 AM

Please learn to pick an appropriate title for your post. That's WHY titles exist. Thank you, and don't be an asshat whining about something you have done WRONG!
January 5, 2007 2:20:33 AM

Quote:
Please learn to pick an appropriate title for your post. That's WHY titles exist. Thank you, and don't be an asshat whining about something you have done WRONG!


STFU and go away.
January 5, 2007 1:11:05 PM

Quote:
Please learn to pick an appropriate title for your post. That's WHY titles exist. Thank you, and don't be an asshat whining about something you have done WRONG!


STFU and go away.

STFU?


You mean Stuff the fat under and go away?

dont get it.
January 7, 2007 2:12:46 AM

Quote:
Please learn to pick an appropriate title for your post. That's WHY titles exist. Thank you, and don't be an asshat whining about something you have done WRONG!


STFU and go away.

So you support the idea of taking a working system and screwing it up? Titles exist for a reason, this isn't rocket science.
January 7, 2007 2:47:24 AM

Quote:
Please learn to pick an appropriate title for your post. That's WHY titles exist. Thank you, and don't be an asshat whining about something you have done WRONG!


Where did this come from? Regardless, this is blatant flaming, you are not a moderator. If you don't like the title do not waste your time reading the posts and furthermore wasting others' timewith useless posts.
January 7, 2007 5:23:53 AM

Quote:
Well now im only 1/2 thinking tonight rofl. Stupid synthahol.,... :) 


Anyway, I know the density will continue to seek equilibrium... but instantaneously.



anyway.... i relinquish my opinion here....

PUt a 120mm fan on top of the case, and be done with this convo.


You deserve a compliment, so I am giving you one. Peace.
!