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It's oh so quiet

S

silverJON

Weaksauce
Joined
Mar 1, 2007
Messages
77
For a year or two now I've had a near-silent air setup, with passive sinks on my bridges and GPU, a Zalman 9500 with a Nexus 92mm fan on my Venice, a 120mm Nexus fan in my PSU, sometimes undervolted a bit, and a Samsung Spinpoint drive with a Zalman cooler, on rubber mounts.

Now things are getting serious, though - I've just got an Opteron 170 (S939) and an AN8-32X board, and they run stably at a 48% overclock (and would probably go higher with new RAM). Trouble is, I've now had to add two extra 80mm fans and still the PWM mosfets hit nearly 85 degrees under load, and the CPU not far off 65 degrees. I've left it now at stock volts and dropped it to a 40% overclock and PWM/CPU are still 75/55 at load.

I replaced the awful thermal mat on the bridges and PWM with AS5 and lapped the sinks, but it didn't do much.

So I'd like to be able to get the most out of my hardware. I'd like a system that runs as quiet as technologically possible, while still adequately cooling my CPU, PWM and GPU (Asus EN7600GS Silent). I'll leave the Nexus in my PSU and the heatpipe cooler on my hard drive, but the PWM sink is linked to the southbridge sink by a huge pipe, so I should probably put either a block or a massive passive heatsink on that.

It's all in a reasonably spacious midi tower, and I'd like an internal unit preferably... I'm not averse to a bit of Dremel-age!

Where on earth do I start?

Cheers!
 
Well not sure what you want but I do want to clairify one thing, the Power Mosfets under the heatsink near the CPU that are part of the voltage regulation circuit for the CPU typically have a rating of 120C in operation with a max temp of 150C. So there is absolutely no concern over what the bios mistakenly calls the "PWM temp". Keep in mind you are still running at stock Vcore so there is no extraordinary load on the MosFETs another indication that the temp you are seeing is of no concern.

However, removing the heapipe assembly and putting AS 5 underneath was an excellent idea. Also you need to check that board flex is still allowing them to contact the heatsink properly and replace the push pins holding heatpipe/heatsink assembly on with proper nuts bolts and lockwashers and screws and torque to 16in-lbs. Then buy a cheap hard drive bay cooler and tear out the 40mm fans. Rip off the bling bling cover off the top of the FET heatsink and hot melt glue or get a scew into the HS and mount one of the fans to it and the southbridge. These units will be silent and the extra forced air will cool things off like crazy. I could not keep my finger on the fins of my DH6 heatpipe for a count of 4, basiclly did the above and now I can lay my finger on it forever. I like to destroy these and you end up with a spare fan. Or buy individual to your needs after measuring. I use these guys (not affiliated in any way), good service, one price shipping makes buying a few fans cost effective.)
http://www.nexfan.com/ev3f5bayhddc.html

So in summary the MosFETS are a bit of a red herring, of no real concern and can easily be tweaked some more with a small fan and some hardware that includes your desire for quiet.

How about a link to your case so we can see what we are working with ?

So do you want to watercool the cpu and possibly the videocard ?
 
Thanks for the advice guys! It's a really great starting point from which I can do a bit of research, now I know where to look.



AppaYipYip: a Swiftech pump sounds perfect. I'd also love a huge passive rad, but I can't spend that much on one. In fact I'm wondering if I can get a car radiator for next to nothing and mount it on the side of the case! That would be an awesome passive radiator. Apart from getting the right size barbs attached, are there any other potential problems with using a car radiator? I don't want to fry my rig...

BillParrish: if replacing the pushpins with nuts and bolts makes a difference, I'll definitely do that. How do I check if the board flex is affecting contact? Your hard drive cooler fan idea sounds really good except that if I'm going water, I'd fit one of these babies to the MOSFETs:
http://www.mips-computer.de/images/abit_an8_32x_mosfet.jpg
They're made by MIPS in Germany.
But then, the southbridge heatpipe wouldn't be connected to anything. I'd have to put your hard drive fan job on that, or even watercool that too...

That water cooling kit does look sweet but I'm in the UK and it would be awkward and expensive to get it imported. The components list will be useful though, thanks.

So... my plans are:

Car radiator to run passively, or double 120mm fan radiator
Swiftech pump
T-pipe
Bog standard 939 block (cheap will do)
Bog standard 7600GS block (cheap will do)
MIPS block for MOSFETS
Cheap block for southbridge, maybe
Cheap block for northbridge, possibly

I reckon I might be able to do the whole lot for under £150 ($300)... is that reasonable?

Aaaand... here's my case! Sorry about the spaghetti... I'll sort it out soon.

CASE.jpg




If I get a fan-cooled rad, it'll go here, I think:

rad.jpg
 
If that would fit you would be sitting pretty.

Most blocks require mounting with the board out of the case so you can easlily shine a penlight from the backside and look for light shining through on all your block mountings. It just depends on how much board flex you get from mounting the cpu block and how much clamping force you use and the physical location of the other blocks/heatsinks.

I had to take a |_| shaped piece of alum channel and fit it just under the top edge of my board to flatten it out.

you can just barely see it in the first pic, better in the second, its covered with a layer of electrical tape so it looks black and I slipped a thin piece of cardboard in there too. Had to file down the motherboard standoffs to make up for the added height. That part of the heatpipe along the top edge would not sit flat without it due to the high pressure I used on clamping the waterblock. might not be a problem with your board. just depends.
http://mysite.verizon.net/ressdxka/id3.html
Didnt realize you were over the pond. Looks like you have it well planned out, cheers !


doh ! see from the pic you probally wont have the "pcb bending issue" I had or if you do I dont really have a solution other than the thick thermal pads they use on some video card coolers for the memory.
 
Ah, thanks, will have a good look with a light under the (currently) sinks next time the board's out.

A couple more questions, though:

How does this XSPC X2O waterblock look? It's cheap, convenient for me to buy and reviewers seem to love it.

Would I get a big temp improvement over air using
this Watercool HTF3 2x120mm rad
or an Alphacool CORA 642 MAXI rad passively
or a hee-uge car radiator passively
or are any of them good, or none of them adequate? I'd be cooling my CPU, GPU, MOSFETs, and possibly two bridges.

(Incidentally, a 642 costs $60 from FrozenCPU, and £79-£90, that's $158-180, in the UK :()

P.S. The big pipe between MOSFET and SB sinks can be removed at the ends without cutting... any reason why I can't keep my SB cool by removing the MOSFET heatsink and clamping that end of the pipe to some bare case metal instead? Nice idea?
clampend.jpg

(Would need a bit of heatpipe bending though... not easy!)
 
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