Someone asked recently what my system was and I answered by saying I have so many on the go & being ripped up & down that it's hard to say. That's not totally true. One system has been a mainstay for most of my serious writing, publlishng, web browsing and email for quite a while. The contents and config of this system changes, but the case & HDDs have not changed.

A couple days ago, I had a glitch that froze the PC and didn't allow power on after shutdown. I knew it was something related to the PSU, so I left the old PSU in place and just patched in another one in a hurry and left the new PSU outside the case. This morn, I was tidying up the case & decided I'd see what happens with the PSU left on the outside: I simply removed the old PSU and left the new one out.

Here are a couple pics:



Components:

Superpower Landmark ATX-298U mid tower case -- very sturdy, totally easy lift off sides, all grills cut away, high density carpet underlay on inside of side covers. Old -- no front ports at all. Bottom of the front bezel is cut away for great airflow. This bottom intake slot hangs over the 1.5" thick piece of closed cell foam the whole PC sits on top of -- to eliminate whatever vibration is left from getting into the floor. Only serious problem with this case has been dust. I keep telling myself I have to do some Bluefront-type filter mods, but never seem to find the time, I do vacuum and wipe down in there occasionally, esp. the HS and HDD area. Amazing how quickly dust builds up; HS give better performance w/o dust.
AOpen AX4GE Max P4 mainboard -- the one used in the SilentTek review
P4-2.53 (533) CPU
Zalman 7000 copper HS @~4V (fanmate1 on 5V feed)
Zalman 300A PSU - Panaflo 80L modded -- it was nearby when I had my emergency! Seems to run ~5V
512MB PC2700 DDRAM
Matrox G400 Max 32mb VGA dual head; stock cooler with 40mm fan replaced with Zalman NB passive cooler (thermal adhesive) -- cooled with a Panaflo 80L @ 5V hanging off the back of the card w/elastic -- see photo -- with 4-PCI slot covers open below AGP port. Still love this thing; try others but keep going back -- as long as I am using analog VGA outputs. When I go to dual DVI, then it will be replaced. Maybe with a new 650 Matrox?
- SCSI card for old scanner
- PCI USRobotics hardware modem
- 2 Panaflo 80L fans @5V

As you can see, the PSU is just sitting on top of the case, with 2 thick weatherstripping foam pieces as feet. The wiring is routed through the PSU hole in the case. It's Panaflo 80L modded.

The 2 Seagate Barracuda IV 40G drives have been my main drives for over 2 years. One holds the OS & programs, the other holds ALL my data, which I place in My Documents. Things like My Favorites, email files, address book -- everything that Windows normally squirrels away in all kinds strange cubbyholes are here in simply named folders. This makes maintenance and backup really easy:

I do uncompressed backup of the Data drive to an external USB or network drive every evening. If the PC goes wonky for any reason, I just pull out the data drive, plonk it into any other Windows machine and I am ready to pick up where I left off in 5-10 minutes of reassigning Special Folders using TweakUI (MS utility).

The drives are suspended in an old 5.25" drive cage (same one shown in my original HDD suspension article) with sewing shop elastic cord -- quite stretchy and spingy; the HDDs really float in there. The Panaflo 80L @ 5V in front is also suspended the same way. The assmbly just sits in the front bottom. You can see the front intake fan grill is completely cut away -- two actually -- an 80mm hole and a 50mm hole.

Here's what it looks like with the HDD cage in place.



Performance --

1) Noise: With the internal PSU, I had a Panaflo 80L case fan on EAR grommets at 6V. It measured ~20 dBA/1m. With the case closed, the noise level has not changed subjectively with the PSU on the outside. I've had it this way for 2 days now, and I notice no difference from before. There is no high freq noise from this at all, only a tiny bit of a lower frequency whirr -- from the fans, I think. No seek noise at all -- either heard or felt on the case.

2) Temps: Since moving the PSU outside, all the temps have dropped by 5~6C. In 22C ambient & (folding @ home 24/7)
- CPU: 52C
- Sys: 44C
- HDDs -- top: 37C, bottom: 35C
- PSU: it's barely moving ainy air but what exhaust there is feels cool to the hand. Gotta be the coolest PSU exhaust air I have ever felt. This is while folding, with ~120W power draw. Power draw is 80W at idle.

I did check at idle briefly -- I think the CPU fell to ~30C or even less. No change in HDDs.

So far, this new arrangement is a success: It's certainly no noisier with one less fan and temps are lower across the board. The only downside is that if I get sloppy while hacking under the hood, the PSU could fall off, yanking components on the end of cables, and break itself, too. BUt it is easier to work inside because there is so much more room...

Anyway, for whoever asked (there were a few) this is one of my reference systems. It is a fast system that I can multitask w/o problem -- I have no need for any more speed for anything I do. Only Acrobat occasionally crashes, but it does that with every PC I've ever used! Under my desk, it is generally inaudible. And no one even sees the external PSU or wire mess (which is all tied together and strapped to the case).

Very nice! More ghetto-tastic than i would have expected from you!

But I do think that it may be time for a new rug on the floor, that one looks a bit frayed.

So am I correct in the fact that now your case has no exhaust fan at all? Convective flow out the open PSU hole is enough to keep the case temps down? Can you feel a flow of air coming out?

Yeah, it's definitely more "ghetto-tastic" than before; this machine usually just gets cast-offs and on-the-fly fixes than any of my others because it's a workhorse that rarely gets a rest long enough for more. I had a PSU fresh air duct in there before, but I have to say the PSU exhaust feels at least 10C cooler than it did before. I guess the rising heat affected it much more than I though it did.

You're right that there are no case fans at all. The 5V Panaflo in front only pulls enough air to cool the drives. I can definitely feel the rising heat at the PSU mount hole; no question there's a farily large volume of air moving through it. Like I said, everything IS cooler by 5C at least. It's quite a shocker, I didn't expect it.

As for the rug, it's a remnant from somewhere else, and its only job is to keep noise down so I don't give a hoot. But if you want to ship over a nice Persian, I don't mind.

Actually I was going to ask that if you got a new one, could I have that old one?

Mike, did you have a PSU duct in this box previously?

yes, I said so...

Man, that's twice this week I've forgotten how to read! Sorry, Mike.

Hey it happens to all of us -- no harm done

Velcro is your friend

I think this is right but correct me if I'm wrong:

There's no exhaust fan just the two exhaust holes
You put the side back on the case
You use some sort of foam behind the case to block sound

Question: Why not use more foam inside the case? b/c it wouldn't make that much of a difference or b/c it's not worth the money?

The entire sides -- left and right -- have high density carpet underlay glued on the inside -- about 1/2" thick. All that is pre-SPCR; I'd use AcoustiPack now. The bit of yellow colored stuff you see there is what's left over from my old PSU intake duct. And yes, the case sides are both in place.

Ya know, I might have to remove my power supply just to test out the case and processor temp difference. I would have figured that NOT having a PSU in the case (where it can move air) would have been a problem. But you've said that all temps have dropped. And what's worse is that my PSU is less efficient than yours. It's an Antec TruePower 550.

I'll try this out once we've thoroughly beaten the MacOS team in folding.

I wonder how well it would work in the SN41G2?

I ran my PSU externally from my Shuttle SS51G - temperatures were about the same (slightly higher with external PSU).

The back case exhaust fan was a Panaflo 80L at 6V, and the PSU was only cooling itself. So when it was removed, the big hole at the top of the back for the PSU became a natural convection exhaust for the entire system, increasing the overall airflow for everything. Hence the improved temps all around. If your PSU forms an integral and important part of case heat exhaust, putting the PSU outside may not help anything.

MikeC, how were you able to make the fan hang off the card? I know you used elastic, but I am still not understanding exactly where it was secured. Where did you attach the elastic? Maybe a pic from a different angle?

(btw, I think this is a clever idea as I beleive the best way to cool gfx cards is to blow air across to an exhaust).

Wedge, it's the simplest, most ghetto way possible. Loop elastic through 2 adjacent mounting holes on fan. Tie elastic over back end of VGA card. The elastic is loose enough so that the fan does not touch the VGA card at all. It just hangs there. The angle at which it hangs is natural. Try it, you'll see how/why it hangs like that.

PS -- don't use a heavy fan. The Panaflo weight does not appear to cause any flexing of the VGA card.

I beginning to think that the best air flow is an open air case. I wonder of anyone has modded the side panel on a case to just be a large grate? I'm seriousely considering this mod. The only draw back is that if I don't like it, I'm stuck with it.

Why not fabricate a completely new one out of modders mesh or similar rather than cut up the existing side panel? It would be less work & probably work better.

Yes. Perfect!

Looking at this setup, I've had a simple idea. I am discussing it with bluefront in another thread but I'd like to widen the range of opinions:

I am thinking of building a rig with an Aerocool HT 101 heatsink. This is a rather curious HS because it allows to connect 2 fans to it in a push-pull fashion. My idea is to duct this HS both for intake and exhaust with something like this duct kit

http://www.xpcgear.com/ockit.html

It's a 80mm ducting kit. The case would be one I've seen, with 2x120mm case fans, one for intake, one for exhaust. I would make away with the proverbial 80mm CPU HS fan and use both 120mm fans in push-pull at very low voltages (<5V). So, the front 120mm fan would do intake (with a filter), connected to the Aerocool HS via the first duct, so that fresh air would be channeled directly to the heatsink. From there, the heated air would run via the second duct to the exhaust 120mm fan, where it would be thrown away. Two 80mm-120mm fittings would be used to connect the fans to the duct. Fans will be of course decoupled, and the front besel in front of the front intake fan will be removed. Fans theirselves will be as silent as I can get them in stores around here.

On sight of MikeC's successes with exterior PSUs, I'd take the silent PSU out, and use convection cooling through the PSU hole. If needed, I'd install a 80mm low-rpm fan in the PSU hole. But I think this won't be needed, because my graphic card is really really modest and the rest of the gear is not really hot (2 Seagates, a passively cooled northbridge and the RAM memory).

In this scheme it's all about creating a air circuit exclusively for the CPU, isolated from the rest of the components. A second point of this setup is to substitute a fast-spinning CPU fan with 2 low-spinning 120mm fans in push pull. The combined strength of both fans could cool the PSU at lower noise levels.

My concerns now are about airflow impedance. I don't know how fast these 120mm fans will have to spin to move enough air so that the CPU remains at a reasonable temp even at full, continued load. I don't know whether this setup is a big impedance one. If it is, and I have to speed them a lot, I could have no noise wins at all, but rather the contrary.

But hey! We are talking about 2 huge fans in push pull!

Bluefront has already said that impedance will be high, and that the 120mm fans will have to be spinning really fast in order to move enough air, so I'll get more noise than if I stick to a 80mm fan on the HS and keep the 120mm's as case fans at minimum voltage/speed.

Anyone?

EDIT: the heatsink can be the aerocool or a coolermaster hyper 6. Has anybody any concerns about the weigh of these tower coolers? I am a little bit concerned myself about the motheboard being bent or even cracked under the weigh of these heatsinks.

It sounds complicated to me... I am always interested in simple solutions. Well, solutions that are simple in appearance but work elegantly because they are the most efficient.

1) The other components in the case still need some airflow. Ducting the intake directly to the CPU means the rest of the case has no intake. Why not do something like a duct to the bottom one or two 5" bays that's usually unused? Then the bottom 120mm fan would benefit the HDDs, the motherboard, the VGA. And you might not even need a back fan at all with the open PSU hole. (In addition to a 120mm fan hole)

2) No question the open hole where the PSU used to be allows a lot of warm air to exhaust. I'd just use a guide, not a duct, to force the exhaust air from the HS to go up back and out. If you duct it, the rest of the case will not benefit.

3) With the PSU on the outside, its Panaflo 80L1A has not ever ramped up -- tho my room temp[ has only been up to ~25C with this setup. I think it will probably go up as we get into summer when the room can hit 28-30C at times.

1-All 4 5" bays are used in my setup. 2 CD units and 2 suspended HDs.

2-It's not complicated. It's just one long duct connecting intake, CPU HS and exhaust. It's just a push pull with a long duct in between.

3-case airflow is done via PSU hole or PSU hole+80mm low-rpm fan.

4-I think I didn't say I would duct the PSU hole. Did I? Either way, it is not my intention.

What about impedance? How fast do you think these fans will have to spin? By the way, how silent is a good quality 120mm at 5V? And at 7V?

Has anyone had problems with the weigh of these "tower" heatsinks (Aerocool/coolermaster)? I mean, is it safe using them? I know the manufacturers say it is safe, but I'd like to hear user experiences. Anyone around here uses these things?

That's the exhaust; you need an intake vent.

i bet you'll get better results without the intake duct.

@Trip: what do you mean?

@MikeC: I could use the exhaust vent for intake with a 120mm fan, duct it to the HS, use a 80mm fan on the HS to suck air out of it, and duct the exhausted air to the PSU hole via a second duct, all this leaving part of the PSU hole free for convection. The intake vent would let air in.

Once more, let me ask you: do you think that the 120mm fans in push-pull would have to spin really fast in order to move enough air through the HS, even though outside air is used? Fast enough to become noisier than a 2300rpm 80mm CPU fan plus case fans? You think I'd be better off noise-wise with 2 80mm fans in push pull mounted ON the Aerocool and ducted for both exhaust and intake?

One other thing: does anybody know of some high tower HS that doesn't force you to mount the fans with an up-down orientation, but rather front-back?

By the way, one more idea: I see you have 3 CD units. Let's imagine you had only 2 CDs, therefore 2 free 5" bays, and 2 HDs. I just thought you could suspend the HDs in the 2 topmost 5" bays. The reason: hot air always travels upwards (at least if upwards the air is cooler). If you put the HDs in the topmost 5" bays, hot air doesn't travel through the other components, which would heat them up, and more importantly, it is not used to cool the CPU.

I guess you'll have thougth of this before, and if you didn't do it, you'll have your reasons. What are they? Seek noise too close to the ear at that height, maybe?


EDIT: anyone can tell me just about how noisy 120mm fans are when fed with 5V? And 7V? Do they move a lot of air with such voltages? And how do they react to impedance?

Kind of a old thread, hopefully someone will read this

anyway

MikeC or anyway, do you recommend moving the PSU to the outside and taking away the exhaust fan in a Antec 3700BQE if there was a high end system in there?

like lots of heat coming out from the cpu and the vid card.

thx
~RaNDoM

RaNDoMMAI --

Easy to try it and see

alright i have a follow up questions since i wanna try this now.

How long can i have cable extensions before it is bad? is there a bad?

I know having long speaker wires is bad.

also, i have a nexus 3000, should i flip it upside down so the air can get to the bottom vents too?

thx
~RaNDoM

Cable extensions? Why do you need anything like that? I don't use any in that set up, cables are long enough. The point is just to get it out of the box. And yes, turning it upside down is better.