Semi-fanless XP-90 possible?

floffe · Post by **floffe** » Sun May 28, 2006 6:18 am

I'm going to upgrade my computer soon, and I was thinking of getting a Lian-Li G50, where the PSU can be flipped over. I was thinking of cooling the CPU with an XP-90, and it seems to take heatsinks that are max ~85mm high, the XP-90 being 75mm without a fan. Do you think using the 120mm PSU fan to draw air through the heatsink would cool enough (from up to 10mm away)? Would it help with a duct of some kind? I'll probably go for an Athlon64 3200+ or something in that range. The XP-120 is quite a bit more expensive than the XP-90, otherwise it wouldn't be much to ask about.

Bluefront · Post by **Bluefront** » Sun May 28, 2006 6:43 am

IMHO....that case is a terrible design to attempt to run fanless using that or any other heatsink. Heat off the heatsink will attempt to go upward toward the top of the case, and there is little venting up there to evacuate the heat. Using the PSU fan to do all the CPU cooling....possible but looks very difficult with that case design.

A better approach would be with a case where the board is horizontal, allowing the heat off your XP-90 to go upward and out a top vent, or through a duct. Like this.

floffe · Post by **floffe** » Sun May 28, 2006 8:40 am

I just got the idea from the tight space there, thanks for your input. Sounds like it'll be much easier having the PSU taking in fresh air and use a Zalman 7000 instead then. Ah well, at least I put the idea out there. Or maybe an XP-120 with a sucking fan and taking out the power supply fan, but a power supply feels a little too hard for a first ever mod.

The thing is that I have the computer in a unit on wheels which limits both width and height, that's why I was interested in that case.

Oh, and it has a 120mm exhaust fan on the top side, so heat should get out without too much trouble.

kentc · Post by **kentc** » Sun May 28, 2006 11:37 am

i am about to build a custom case and i've been doing some experiments with airflow over my xp-90c (copper version, as expensive as the 120 and almost as effective. xp-120 won't fit my cramped matx mb). cpu is 3200+.
with some ducting a nexus 92mm at 850rpm/about 6v can keep the cpu at 45 degrees celsius from 5cm (and at a 90 degree angle!) away blowing, double cpuburns running, 46 degrees sucking. idle is 31 degrees and ambient 21 degrees.

so i think your idea would work - the xp's only need a slight breeze to keep the amd's cool.

edit - forgot to mention, cpu is undervolted to 1.3v at 2000mhz.

floffe · Post by **floffe** » Sun May 28, 2006 12:36 pm

How is your board rotated there: does the hot air rise from the XP-90C into the duct, where it's taken out by the fan?

Actually, now that I think of it it probably wouldn't be too bad if the hot air rose in the G50 either, the top fan takes it out of the case pretty soon anyway. I guess the main issue would be making sure that the PSU fan kept some air going through the heatsink and not just taking it from the rest of the case.

kentc · Post by **kentc** » Wed May 31, 2006 1:14 pm

in my tests (and the coming real world application) the board will be "upside-down" with the cpu at the bottom of the case and standing up. the fan will be sucking air from underneath the case, over the xp-90, the pvms and the memory, nb, sb, hardrive, powersupply and then vented out the back.