PSU on bottom or top?

kees · Post by **kees** » Sat Sep 11, 2010 6:13 am

Hi,

I'm doubting between an Antec SOLO and a Antec P183.

What is better, PSU at bottom or top of the case?

~El~Jefe~ · Post by **~El~Jefe~** » Sat Sep 11, 2010 7:09 am

if you have fanless like me, top.

otherwise, it seems bottom for all setups.

kees · Post by **kees** » Sat Sep 11, 2010 7:32 am

~El~Jefe~ wrote:if you have fanless like me, top.

otherwise, it seems bottom for all setups.

thanks
Why? I would love to see some good (scientific) sources for this...

~El~Jefe~ · Post by **~El~Jefe~** » Sat Sep 11, 2010 7:51 am

science is whatever I freakin say so here it is:

Fanless psu's need..... a fan.

Bottom mounted cases have no.... fan.

SPCR setups have less fans than gamer cases which are not silent, yet SPCR people like me, game.

So, what happens best is that the rear exhaust fan pushes air out and takes IN air through the psu open vents. My psu has 1000's of holes on it and is made of heavy aluminum. If I put my

scientific hand of irrefutable logic

on the back of my psu, I feel the air being sucked in.

-------
A bottom mounted psu with a Fan inside it does not suck up hot air from inside the case. In truth, it is very difficult to make a silent setup that has a fan psu not hindered by the exhaust fan. Two fans next to one another at 90 degree angles (as measured by science) pushing UP and the other to the SIDE fight for air and wind up heating up the system and the psu.

So, put it on the bottom and you lose both the problems of system heat going into the psu and the problem of a competing exhaust fan.

And, on another note: There is no science in Germany. David Hasselhoff was on your top 10 charts for a long time.

please keep him.

tim851 · Post by **tim851** » Sat Sep 11, 2010 8:59 am

I preferred a top mounted PSU when I ducted my HR-01 Plus to the rear exhaust fan, because the duct created an actual dead spot right where the VRMs are and the PSU, being slightly recessed to the right normally, was the perfect vent for that dead spot.

When I build an Office PC for my mom a while ago I only put a Scythe Shuriken with fan in there and a PSU. Works too. When PSUs had an efficiency of 70% and created a lot of heat themselves, not dumping case heat on them was a good idea, but in this day and age of 80 Plus Gold certified PSUs abound, I don't think it really matters anymore.

~El~Jefe~ · Post by **~El~Jefe~** » Sat Sep 11, 2010 1:21 pm

a top mounted psu slows down exhaust speed if placed on top, unless you have 2-3 medium speed 120mm fans pressing in air into the case.

it can work for all sorts of setups. that is a good point that the higher quality psu's dont add a lot of heat. I was more concerned with the psu getting cooked on a daily basis by components, lowering efficiency and lifespan.

I think all problems with silence and cooling can be solved if you place 2 or better yet 3 fans blowing in for positive pressure. this lowers system temps increasing cooling efficiency, less dust crammed into cracks from suction, less dust on parts that have no active cooling, and gives the PSU full quantities of air that it doesnt need to fight for with the exhaust.

I have tested these things to the Nth degree. I noticed one day that if I LOWERED my 120mm Papst exhaust fan, my fanned PSU would get quieter... I realized the rear exhaust was causing a lack of air and therefore a suction, fighting the psu from cooling itself and ramping up. It was a seasonic 430 too, a good psu. I then realized I had to scrap that case and go for 2 fans at least blowing in. My new build has 2 on the side and one on front. Cant wait to get it all in the mail this week : )

danimal · Post by **danimal** » Sat Sep 11, 2010 5:38 pm

kees wrote:Hi,

I'm doubting between an Antec SOLO and a Antec P183.

What is better, PSU at bottom or top of the case?

there is more involved in those choices, than just the psu location.

Post by **NeilBlanchard** » Sun Sep 12, 2010 3:35 am

All else being equal (like air flow around the PSU) then the bottom of the case would have slightly cooler air. The top is more likely to have the heat from the PSU go out of the case, and not into the rest of the case.

kees · Post by **kees** » Sun Sep 12, 2010 3:36 am

danimal wrote:
kees wrote:Hi,

I'm doubting between an Antec SOLO and a Antec P183.

What is better, PSU at bottom or top of the case?
there is more involved in those choices, than just the psu location.

I believe that. I'm pretty new to this and I would like a recommended way of building a silent pc, also with a budget in mind. (I have most of the components in mind, but I doubt about the silent part e.g. case, PSU, fans, HS and how to build it properly).

Suggestions are welcome.

~El~Jefe~ · Post by **~El~Jefe~** » Sun Sep 12, 2010 9:24 am

well, what is your budget and goals?

kees · Post by **kees** » Sun Sep 12, 2010 9:40 am

~El~Jefe~ wrote:well, what is your budget and goals?

That is discussed here: viewtopic.php?t=59973
Goal -> workstation | DAW

possible setup:

Processor: i5 750
Heatsink: ?
MB: Asus P7P55D
Memory: Corsair XMS3 4GB(2x2GB) PC3-10666
HDD: 2 x Western Digital WD5000AADS (Bulk, Caviar Green) (500GB)
case: Antec SOLO or P183
Fan: Nexus 120mm Real Silent case fan
DVD: Lite-On iHAS124 24xDVDRW
PSU: Seasonic S12II, 380Watt, ATX

Now it's the question what is the best approach to get that stuff silent and how to build the components into a computer

thanks in advance.

~El~Jefe~ · Post by **~El~Jefe~** » Sun Sep 12, 2010 10:47 am

can you instead put in a fanless psu? makes life easier.

and get 3-5 fan bay controller.

kees · Post by **kees** » Sun Sep 12, 2010 12:06 pm

~El~Jefe~ wrote:can you instead put in a fanless psu? makes life easier.

and get 3-5 fan bay controller.

fanless psu in the P150 or P183? (just to be sure...)

fan bay controller? What are good ones?

~El~Jefe~ · Post by **~El~Jefe~** » Sun Sep 12, 2010 4:47 pm

The best one made is this one:

Zalman Combo

It is made from very good quality components, great machining on the front as well. It has 4 voltage controllers and 1 PWM controller. Good if you get a big heatsink like a scythe with a PWM on it, you dont have to swap it out.

Aside from that, I have a new one that seems really neat but it is 1/2 the price and not as fancy. It controls 6 fans on voltage. It has high medium low, which is max 12 volt, minimum like 5.5 from what I gather and then like 7 volt medium. It is push button! I like it because I can make certain fans medium thrust and others low.

Aerocool uses tiny components but has a huge 12 watt per channel safety claim. My electrical engineer friend was really impressed by it. I dont know how long it will last however, it hasnt been tested like that.

6 channels though is impressive. It doesnt look nearly as good as machined aluminum, of course, but it looks kinda cool

Aerocool F6XT

If you want 3.5" bay, as those are 5 1/4" bays, you should go:

This guy is neat

There are other 3 fan controllers I fully recommend but I thnk you might need 4 fans?

JamieG · Post by **JamieG** » Sun Sep 12, 2010 5:33 pm

kees wrote:fan bay controller? What are good ones?

I really like my Scythe Kaze Server, which has manual, semi auto and automatic fan speed modes.

From memory, automatic mode turns fans off until temperatures on a corresponding temperature probe exceed a certain level, then the fan turns on to a set rpm.

The temperature-based speed increase from a minimum set speed to max fan speed in Semi Auto fan mode (which I currently use in my P182) is more useful for a gaming machine.

The Zalman controller recommended above looks pretty decent if you just want manual fan control though.

~El~Jefe~ · Post by **~El~Jefe~** » Sun Sep 12, 2010 6:25 pm

I would say the Scythe is great but:

A: never used it - doesnt mean much as Scythe is great company
B: I dont know if it is voltage or pwm control

The zalman is like sweet. It has heatsinks and extra high quality parts on the voltage controller things. It goes a little past 5volts too if i remember it right now I think 4. The knobs are smooth and move slowly. I threw mine out like a moron with my old case!!

kees · Post by **kees** » Mon Sep 13, 2010 2:07 am

NeilBlanchard wrote:All else being equal (like air flow around the PSU) then the bottom of the case would have slightly cooler air. The top is more likely to have the heat from the PSU go out of the case, and not into the rest of the case.

What is your opinion, does it matter if the PSU is fanless or not, to put it in the bottom? Or do you think a fanless PSU belongs always on top?

kees · Post by **kees** » Tue Sep 14, 2010 10:13 am

Pfff really hard decision. The antec solo is editor's choice, but I got the feeling the p183 is more silent at the end. Also Antec recommends the p183 over the solo...

But the p183 is LARGE.... and more expensive. I think I go for an PSU with a fan...
It should be possible to build a silent DAW system, with a small video card with the Antec solo and the psu with fan right?

~El~Jefe~ · Post by **~El~Jefe~** » Tue Sep 14, 2010 12:28 pm

kees wrote:
NeilBlanchard wrote:All else being equal (like air flow around the PSU) then the bottom of the case would have slightly cooler air. The top is more likely to have the heat from the PSU go out of the case, and not into the rest of the case.
What is your opinion, does it matter if the PSU is fanless or not, to put it in the bottom? Or do you think a fanless PSU belongs always on top?

well, I dont know what these people think. I do not believe our reviewers employ fanless psu's in their own rigs.

I have about 6 years of only fanless psu's and I can say that in a silent setup, you want the exhaust fan or intake fan to be next to the psu. It is a breather for the case, or else on some strange cases, theres a fan blowing on it.

traditional cases = fanless psu's.

my next statement should clear it up: Fanless psu's exist the way they are because they are made assuming that a person has a traditional ATX setup. They are designed to last 5+ years in this environment. I do not think they were ever intended to be used in a bottom isolated place. Some isolate them and THEN put a fan on them. reason is that a 120mm nexus or scythe on likt 7 volts is essentially inaudible and combines the best of all worlds:

A) a psu that never needed a fan to thrive
B) a fan to keep it cooler than it was ever intended so it lives even longer thats inaudible anyways.

none of my setups use bottom mounted psu's. There are many good cases that have top mounted psu's. Some of the "silent" cases are bottom mounted which is stupid because:

silence is no moving parts
silent cases should be made for setups that have:
no moving parts
Silent cases rely on moving parts to be...
*BUZZER SOUNDS* XXX
Verdict:
silent cases need more moving parts than non silent cases and therefore are more noisy.

strange, yes.

Jipa · Post by **Jipa** » Tue Sep 14, 2010 12:43 pm

My passive PSU sits at the bottom and is ATM happily feeding Q9450 + HD5850. I don't know what level of "quiet" you aim at, but in this system having the PSU sit at the bottom works like a charm.

For other builds I've prefered the PSU not to have anything to do with the case air circulation either, but this depends on the system heat output and the particular PSU being used. Some tend to ramp up way too soon if heated, etc.

But for you I'd grab the Solo. The P183 seems kinda... excessive if you only need a single 5,25" and another 3,5" bay. What GPU are you going to use? You forgot to mention that.

kees · Post by **kees** » Tue Sep 14, 2010 12:52 pm

Jipa wrote:What GPU are you going to use? You forgot to mention that.

I have a simple matrox card, passive cooling, very old...
Chance I will upgrade it to a ATI card (or get a MB with onboard gpu), but it's not the plan to get a huge card...

@~El~Jefe~ downside, a fanless psu is three times the price of a decent psu with fan...

victorhortalives · Post by **victorhortalives** » Tue Sep 14, 2010 2:29 pm

~El~Jefe~ wrote:
kees wrote:
NeilBlanchard wrote:All else being equal (like air flow around the PSU) then the bottom of the case would have slightly cooler air. The top is more likely to have the heat from the PSU go out of the case, and not into the rest of the case.
What is your opinion, does it matter if the PSU is fanless or not, to put it in the bottom? Or do you think a fanless PSU belongs always on top?
well, I dont know what these people think. I do not believe our reviewers employ fanless psu's in their own rigs.

I have about 6 years of only fanless psu's and I can say that in a silent setup, you want the exhaust fan or intake fan to be next to the psu. It is a breather for the case, or else on some strange cases, theres a fan blowing on it.

traditional cases = fanless psu's.

my next statement should clear it up: Fanless psu's exist the way they are because they are made assuming that a person has a traditional ATX setup. They are designed to last 5+ years in this environment. I do not think they were ever intended to be used in a bottom isolated place. Some isolate them and THEN put a fan on them. reason is that a 120mm nexus or scythe on likt 7 volts is essentially inaudible and combines the best of all worlds:

A) a psu that never needed a fan to thrive
B) a fan to keep it cooler than it was ever intended so it lives even longer thats inaudible anyways.

none of my setups use bottom mounted psu's. There are many good cases that have top mounted psu's. Some of the "silent" cases are bottom mounted which is stupid because:

silence is no moving parts
silent cases should be made for setups that have:
no moving parts
Silent cases rely on moving parts to be...
*BUZZER SOUNDS* XXX
Verdict:
silent cases need more moving parts than non silent cases and therefore are more noisy.

strange, yes.

Another data point in this argument is the Antec 3480.

This IS an ideal case for a fanless PSU - why ? - because the top compartment has a top ventilation grill (designed for the original Antec PSU.)
As it happens the Antec PSU is not very silent and cries out for a replacement.

Put a fanned PSU in it and the fan usually exhausts upwards = noise directly output to the user's ears.
BUT
Put a fanless PSU in it and the grill aids in the venting of the PSU heat as well as giving no noise out.

I have such a case with only one moving part in it at all - the 7v Scythe case fan in the lower compartment.

Luke M · Post by **Luke M** » Tue Sep 14, 2010 9:35 pm

victorhortalives wrote:Another data point in this argument is the Antec 3480.

This IS an ideal case for a fanless PSU - why ? - because the top compartment has a top ventilation grill (designed for the original Antec PSU.)

Agreed. A passive power supply in that case is truly passive, not stealing system fan airflow.

But looking at this picture: http://www.silentpcreview.com/article763-page4.html ...I wouldn't want to try to make an extra long (>140mm) power supply like the Seasonic X-400 fit.

victorhortalives · Post by **victorhortalives** » Wed Sep 15, 2010 12:38 am

Quite right. This is exactly the problem with this case - made worse if there is a CD unit to be housed AND the PSU doesn't have modular cabling !

Some folks on the forum have drilled extra holes etc to make room, but that tends to defeat the purpose of having two chambers.

Fortunately the Silverstone 300 does fit - just about.

quest_for_silence · Post by **quest_for_silence** » Wed Sep 15, 2010 3:19 am

kees wrote:It should be possible to build a silent DAW system, with a small video card with the Antec solo and the psu with fan right?

Among my system I have a Solo with a Zen 300 (and an HR01 ducted) since 2008 and it works flawlessly, even with ambient up to 28Â°C: but I dunno if it may also work with a cpu >> 65W (like a quad).

The system sports just one 800rpm Slipstream (exhaust) but it's actually always stopped (and no intake fans).

But, to tell the truth, IMO it isn't substantially quieter (even if it runs hotter) of another system I own with the same cpu (a slightly undervolted and mildly overclocked E5400, ~3,8GHz at ~1,125 vid) with as many as three fans (NSK3480, EA-380D modded with a Noctua R8 running at ~400rpm through an external 3 pin header controlled by SpeedFan, 500rpm exhaust Slipstream via a std 4P molex, and a Scythe Kabuto with its fan run at ~300rpm through a std 3 pin header, also controlled by SpeedFan). Even at night.

Regards,
Luca

P.S.: if you rather go with a bottom mounted PSU, the Antec Mini P180 is a bit less tall than the Solo (and you also may find some a bit cheaper than the Solos).

~El~Jefe~ · Post by **~El~Jefe~** » Wed Sep 15, 2010 5:27 am

I dont think people understand fanless psu's.

they are not passive. They say in the box even how they use system air movement to keep them cool.

They are not passive.

they are fanless. They need a fan still.
Anyone can make any dink, dribbling at pIII speeds to watch 480i ripped video for 30 mins box and not have a fan on their fanless psu. That is because they are burning like 90 watts

Burn up past 180 watts on load, and well, you need air movement if you want it to last longer than an spcr review on fanless psu's.

victorhortalives · Post by **victorhortalives** » Wed Sep 15, 2010 5:34 am

Mike Chin - Care to comment ?

quest_for_silence · Post by **quest_for_silence** » Wed Sep 15, 2010 5:46 am

~El~Jefe~ wrote:That is because they are burning like 90 watts Burn up past 180 watts on load, and well, you need air movement if you want it to last longer than an spcr review on fanless psu's.

Jefecito-with-pock-faced-wrath, you are right, but noone has told here to overstress a fanless PSU, or so it's seemed to me.

My own systems are all on the low side of actual power consumption, but that Solo/Zen combo still can handle a two hours stress test (yeah, I don't game/fold on it: for those tasks I use an M12D and a Signature as PSUs).

Regards,
Luca

kees · Post by **kees** » Wed Sep 15, 2010 8:26 am

Hmm so p150 with fanless cpu or p183 with psu with fan.... hmmm

possible setup:
Antec solo
MB: Asus P7P55D
Seasonic X-400, 400Watt,
Intel Core i5 i5-750 / 2.66 GHz processor
Prolimatech Megahalems
Noctua NF-P12 120mm Fan, 1300rpm (cpu fan)
Noctua NF-S12B ULN 120mm Fan, 700/500rpm (2 x)
Corsair XMS3 4GB(2x2GB) PC3-10666/1333MHz
WD AV GP 500GB SATA II 32MB (1x)
WD RE3 Enterprise 500GB, 7200rpm, 16MB, SATA2 (1x)

quest_for_silence · Post by **quest_for_silence** » Wed Sep 15, 2010 12:13 pm

kees wrote:Intel Core i5 i5-750 / 2.66 GHz processor

Choose the i5-760: the 750 is phased out, or so about.

kees wrote:Noctua NF-P12 120mm Fan, 1300rpm (cpu fan)
Noctua NF-S12B ULN 120mm Fan, 700/500rpm (2 x)

Nexus and Scythes are far better (and also cheaper).
A Kaze Server or a Zalman MFC-1 plus might be also a good idea.

kees wrote:WD AV GP 500GB SATA II 32MB (1x)
WD RE3 Enterprise 500GB, 7200rpm, 16MB, SATA2 (1x)

If you go with 500GB drives, go with 2,5" ones in Scythe enclosures and suspend them (so I did in my Solo).

Regards,
Luca

PSU on bottom or top?

PSU on bottom or top?

Re: PSU on bottom or top?

Re: PSU on bottom or top?