Too hot? Get a cardboard box!

[parish]

My main machine has dual Athlon MP2800s and it runs very hot and very noisy. OK, so it's a cheapo case which doesn't help but even with 80mm intake and exhaust fans I was still getting CPU temps of 49-55C and Northbridge temps of 32-38C.

The case itself got noticably warm and since I intended to line it with acoustic foam the problem was only going to be made worse. Hanging a thermometer in the case revealed case temps of 35-40C with the side on, dropping to only 32-35C with the side off - I once saw 38C with the side off so there must have been times when it was >40C with the side on. The case temps were so high that even my TV card needed a fan - which you can see on the case floor in the first pic.

The solution had to be ducting as there is no room with dual CPUs to fit any kind of high performance HSFs, and anyway, they wouldn't make much difference without dramtically increasing the volume of air through the case.

Using the box the acoustic foam came in I knocked up a duct/plenum chamber that fitted over the CPUs and the Northbridge, hacked out the back of the case to fit a 120mm/14dB/58cfm SilenX and put the old 80mm exhaust fan on the front as a second intake. Whilst modding the case I drilled a hole in the back and fitted a wiring grommet so I could use the thermometer without taking the case side off.

The results were superb. The CPU temps are now 36-38C most of the time and the extremes I've seen are 35C and 39C - I can't get them to 40C even running apps using 80+% CPU. The Northbridge now runs at 25-26C and the ambient case temp is 21-22C - only 1-2C above room temp.

The SilenX is hooked up to one of the CPU fan headers and the mobo monitor reports it running in the low 1400s rpm. Since it is a 1600rpm fan I guess it is struggling to drag 58cfm through the 3 heatsinks so I should be able to reduce the voltage - and on the intake fans as well.

The noise level hasn't fallen as much as I'd hoped despite the acoustic foam, but I think that the duct is acting as a sound box and amplifying the noise of the air being sucked through the heatsinks.

Butt-ugly? Yes, but I'm not into case windows etc. so it doesn't matter although I plan to make a new duct out of plastic - this one is a bit of a pig to locate and needs pushing down onto the heatsinks using a screwdriver through the fan.

Question is, do I get a Blue Peter badge for my cardboard duck...err...duct?

http://www.magichamster.com/pc001.jpg

http://www.magichamster.com/pc003.jpg

http://www.magichamster.com/pc004.jpg

http://www.magichamster.com/pc005.jpg

http://www.magichamster.com/pc006.jpg

http://www.magichamster.com/pc007.jpg

[latency]

nice job ;)

Had you thought of the amount of dust in there though?

It'll be acting as a nice blanket on all your cards... Give it a blast with some canned air if I were you!

[parish]

I gave everything a good clean when I stripped the machine to cut the fan holes out. There is a filter over the original intake fan, but it's not very effective. I still need to mod the front of the case to improve filtration and cut the noise down - one of my HDDs makes an annoying high-pitched "screeching" noise (not the bearings - it's a "feature"). My plan is to find a pleated paper air filter from a car, or more likely a large motorcycle for the size I need, and fit it in the recess where the drive bays are.

[muddyfox470]

fire hazard?

some hints, tidy those cables, an intake fan and an exhaust will still help, but use dust filters as dust can cause major problems, if you dont have enough space for an exhaust on the back, drill a hole in the top of the case to allow you to fit a blow hole at the top (where most hot air accumulates) obviously tho, take ALL the components out of the case first!

otherwise nice system, can i ask what mobo is that, and what ram does it support? also what do you use the system for, i.e. why do you have a dual system setup?

cheers

ian

[parish]

fire hazard?
It doesn't get that hot ;)

Yes, I have to tidy the cables, but not until I've finished sorting the noise/heat issues. It does have two 80mm intake fans but I can't see an exhaust fan making any difference as the case temp is now only 1-2C above room temp, plus it will potentially rob the CPUs of cooling.

As I said in reply to L4T3NCY I'm planning on addressing the filter issue.

can i ask what mobo is that, and what ram does it support? also what do you use the system for, i.e. why do you have a dual system setup?
It's an Asus A7M266-D, 1Gbyte PC2100 ECC RAM, 73 & 36 Gbyte 10Krpm Ultra 160 SCSI disks, which get bluddy hot - almost to hot to touch, which is why one of the intake fans blows over them.

I've got a dual-CPU box mainly for software development. I use a lot of Open Source s/w and being able to build an entire OS (FreeBSD) from source in just over 20 minutes is useful. Plus I occassionally use it for work, I'm a Software Engineer, so the same benefits apply there.

Even if you don't use SMP-capable software there is still an advantage if you run more than one program at a time as you effectively have two uniprocessor machines.

[six5tring]

well tis made me smile today :D thankyou! - six