So I'm running my P4 fanless using a Zen heatsink and a Fortron 120mm PSU. Here's a few mods that might make the whole thing run cooler....

1....relocate the 120mm fan outside the PSU rather than inside. This would place it closer to the CPU heatsink for better CPU cooling and would open up the inside of the PSU for better/less-cramped airflow. This could be done with a slightly thinner 120mm fan, by some trimming on the stock fan, or by moving the PSU up slightly(with some case mods). I've already moved the PSU 2.5" back into the case to line up better with the Zen. Another slight re-location wouldn't be a big deal.

2....Modify the output grill for better airflow by enlarging the output holes, or eliminating then entirely. Re-locate the PSU AC plug by hard-wiring an AC cord to the PSU and running the cord to the bottom of the computer, then out. This would substancially increase the available PSU airflow output area.

3....Modify the top of the PSU by turning it into a large aluminum or copper heatsink that extends out of the computer case through a large hole. This upper PSU heatsink could be very big, depending on what size heatsink I can find.

I'm open to ideas. I think the present PSU design could be improved with a few DIY modifications.....

1) you may find that placing the fan closer to the cpu heatsink may not improve your cpu temperatures. as with all axial fans, there's a dead spot near the centre/hub which is best dealt with by having the fan about 30mm away from whatever it is you're trying to cool.

2) i think it'd be worth your while to remove the psu's rear grill, but relocating the ac plug would be too much work for too little gain. also remember you're going to need to put some kind of fingerguard over the psu anyway, otherwise you (or someone else) could easily get shocked.

3) i'm not sure how effective modifying the top of the psu will be. the psu casing does get hot but that isn't the source of the heat (if i remember correctly, the mosfets are) so it wouldn't be worth the effort.

What about putting the fan under the HSF so it has no intake restriction?

chylld......I had my Fortron apart recently to replace the stock fan with an Evercool fan. What interested me was how tight everything was in there. It is bound to be an airflow restriction when you stuff a 120mm fan, and everything else, into ATX form factor PSU. Since the manufacturer is stuck with that size restriction, it stands to reason an ATX PSU can be modified for better performance, if the modder is not restricted to a certain size. That's why I purpose to move the 120mm fan outside the PSU case.....outside the ATX form factor.

I also think the effects of the size of the fan hub is diminished by the 120mm size. That's why I want to place this fan slightly closer to the Zen heatsink. Right now there's about 35mm between the PSU fan and the Zen. I think the PSU and the Zen would benefit by the move of the fan to the outside of the PSU case.



Also... when you look at the AC plug on the back of the PSU, it takes up at least 1/5, maybe more of the available output area. So I think removing this obsticle to airflow would be a benefit, more than just a little.

Finally....Turning the top of the PSU into a passive heatsink would be an easy mod, couldn't hurt anything, and with proper construction could help with cooling. I'm not trying to run a passive cooled PSU, but some passive cooling would be a benefit.

HammerSandwich.....I don't get it.

I'm trying to address issue of using a thinner fan or moving the PSU. If you put the fan under the HSF, blowing up through it, the problem goes away. In addition, fans seem to work better with any restriction on the exhaust side, so that's what I'd try first. Anyway, I'm glad to see the Zen has answered that ancient SPCR koan: "What is the sound of one fan spinning?"

Stage one of this mod project is finished.....the 120mm Evercool fan in the Fortron has been dropped down, closer to the CPU heatsink, about 30mm closer. If it works, it should cool the Zen heatsink better because more of the airflow is through the fins. But more important from a noise standpoint, it has opened up the interior of the PSU for better airflow....quite noticeably better. This should allow me to run the PSU fan slower/quieter, with the same cooling potential.

While I had the PSU open, I found several potential problem areas...see the photos. One heatsink was almost touching the PSU case. Several wires were resting against the sharp edges of the heatsink...not good. The internal wires were a mess....I fixed the problems, as well as doing the fan mod.

If anyone wants to attempt this mod.....observe care when inside the PSU. You could get a nasty shock. If you cut the flanges of a plastic fan, don't try a snipper....grind the plastic off instead. And for sure.....this mod may not work well with all configurations because of clearance problems. Measure carefully before you start, then measure again.

I'm using this PSU as my only exhaust fan...that's the reason for the mods. But I do think this mod would help the airflow through all 120mm PSUs, allowing quieter operation.

Fortron Mod

I'm still working on the other mods to this PSU setup....

What about drilling holes in the top to exhaust the air out of the psu? This way the fan blows air over the HS and the hot air exits out the top instead of making a 90 turn. You'd have to drill the case as well and worry about direct noise leakage. *shrug* just a thought. Keep modding, youre a wealth of ideas for us noobs.

Just to warn people, my fortron looks totally different, not only does my version have an extremely annoying fan, but the heatsinks in my model seem to be of lower quality and in general my fortron doesnt compare with bluefront's, strage...

~EO

My Fortron came in a blueish Fortron box, and it's a dullish silverish colour, with different heatsinks if I recall correctly.

This Fortron 300w came from CompUSA.....It has a chrome case, and blue lights in the fan. I think it is also sold as an "Aurora". But it is a Fortron Source PSU.

I did not like the fan or the fan operation of this PSU either. That's one reason I changed the fan to an Evercool fan.....and I control the fan speed with an external controller in the front of the computer. IMHO...that is far superior to the OEM Fortron setup.

My Fortron (from NewEgg) sounds exactly like Viperoni's description.

Thanks for the photos, BlueFront. That's a great way of bringing the fan out. It did not even occur to me to do that.

Well I've run this new setup for several hours.....it's a success. I hope some of you guys are brave enough to experiment. Since the PSU fan is cooling my CPU, I judge CPU temp changes to determine if this mod was worth-while.

To maintain an idle temp of aprox 33c, with this PSU mod I was able to reduce the PSU fan speed by 200rpms. The output temp of the PSU remained unchanged.

But more amazing......running CPUBurn for over an hour, running the PSU and the intake fan at about 1350rpms, the max cpu temp was 50c. With the previous PSU setup(same fan), I had to run both fans nearly 1800rpms to remain under 53c. The only change was the fan re-location. I can hardly believe it. I'll have to run the tests again to prove it to myself.

FWIW....I suppose if you could find a thin 120mm fan, you could mount it on the outside of the PSU, without having to cut a bigger hole. I think a 25mm thick, 120mm fan is available. Very successful mod so far.

Edit...I ran the CPUBurn tests a second time with the same results. The output temps of the PSU remain unchanged from the original setup. I am not sure if that output temp is the best measure of PSU internal cooling...but it seems to be. The PSU never feels even warm with the output at 30c and the CPU at max.

This looks like a very good idea. I was thinking about moving the PSU fan lower just to reduce the noise of the fan blades passing over the nearby heatsinks...

Bluefront, maybe now that the fan hub being further away from the actual stuff inside the PS, is allowing for better overall PS cooling?

bluefront, i am looking at the pictures of your fortron PSU mod and the last picture is confusing me: it looks like there is a fan on the other side of the heatlane zen HS. what is it?

Grandpa....that's a backup CPU cooling system. It's controlled by the Silent-Tek utility of the A-Open board. It only turns on when the CPU gets hot. Right now it turns on at 48c.

I guess I worry too much about heat, since the fan only turns on with bench-marking programs. But the A-Open board is set up for this sort of back-up cooling if you want it. Silent-Tek works perfect for this sort of use...it's completely automatic. You can set the on/off temps to suit yourself. That particular fan glows red when it's on, so I can tell if it's working. As the system boots, silent-tek tests the fan for a minute or so...and if it detects a problem warns you with a pop-up. When it does turn on, it's speed is adjusted by the M/B. And since this fan has no external venting....it is almost inaudible at max rpm. I like it. It's just an added layer of protection. Should any crashing occur....this fan defaults to wide open, and glows red.

sounds interesting and it gives me ideas for a project to try with the zen HS. but i know just about nothing about the silent-tek utility. is the temperature at which the fan kicks in adjustable? if the fan always goes at full throttle and the CPU shut off temperature is at 67'C (?), i'd be tempted to put the threshold at 58-60'C. is that possible?

This particular M/B was the subject of an SPCR review which explains the Silent-Tek system. MikeC apparently has one running in one of his computers...see it in the gallery section.

You can set your own temp point for two different fans. I'm only using the cpu channel for the Zen back-up fan. Mine is set to turn on at 48c....at which point it is running about half speed. If the monitored temp continues to rise, the fan will speed up. So what you suggest would work just fine...

Hi I have been reading these forums for a while now. When I was reading this thread an idea popped up in my head.

If it helps on the airflow to move the fan a little away from the components. Wouldn't it help further to tilt the fan, so the blowing direction is pointing a little towards the exhaust area ?

Well it might help with cooling the CPU (in this setup anyway). But remember the internals of the PSU are also using the airflow for cooling, so most of the airflow should go through the PSU heatsinks. And I'm not an advocate of running any fan off a level or vertical orientation. That's just me though.