HSF for AOpen i855GMe Pentium M Mobo

Edwood · Post by **Edwood** » Wed Jun 29, 2005 8:50 pm

I have the AOpen i855GMe Pentium M Mobo, and can't stand the stock HSF.

It has what looks to be standard Intel P4 retention bracket. So would it be possible to use a HSF that uses through hole mounting? Otherwise, I don't think most HSF's that use the retention bracket will clamp down enough to have solid contact with the CPU die because of the lack of a heatspreader like the P4.

I am thinking of gettin the ASPIRE X-QPACK case, so I would like to find one that could cool it passively (no fan on the HSF) where the 120mm fan would do the job, either with just the air if circulates or via ducting.

-Ed

Post by **Ralf Hutter** » Thu Jun 30, 2005 4:18 am

Read my review of this board and it's followup article. This situation is expressly discussed. Lack of clamping pressure on the CPU is not an issue at all.

I personally use a Zalman7000AlCu. It works flawlessly, as should the vast majority of other S478 heatsinks.

mco_chris · Post by **mco_chris** » Thu Jun 30, 2005 6:17 am

I tried the Thermalright XP-120, Swittech MCX478-V, and the Scythe NCU-1000 and NCU-2000 heatsinks and they did not work on this board.

The Thermalright XP-90C can work, but it's hard to install without putting uneven pressure on the CPU die. I did install it once, but when I revmoved it, a corner of CPU die had actually dented the bottom of the heatsink due to uneven pressure while mounting. I'm lucky I didn't break the CPU die.

I couldn't use the supplied back plate and retention bracket that came with the XP-90C. Due to electronic components on the board and the angled CPU, they don't fit. There's a big capactior under the CPU that prevents attaching a solid base plate there.

You're right about the clamping pressure. I'm using the Zalman 7000 now, but was not happy about the clamping pressure. The heatsink would move around and you could feel the hesatsink grease squishing. I added some small shims under the fan and between the mounting arms and the retention bracket to increase the clamping pressure. It's a little better now, but not perfect.

Let us know if find a heatsink that works!

Post by **Ralf Hutter** » Fri Jul 01, 2005 5:09 am

mco_chris wrote:You're right about the clamping pressure. I'm using the Zalman 7000 now, but was not happy about the clamping pressure. The heatsink would move around and you could feel the hesatsink grease squishing. I added some small shims under the fan and between the mounting arms and the retention bracket to increase the clamping pressure. It's a little better now, but not perfect.

Be aware that Intel calls for only 14.4 lbs of clamping force on the heatspreaderless Pentium M CPU, as opposed to 75 lbs of force on the heatspreader-protected Pentium 4 CPUs. I've found the pressure applied by an unmodified Z 7000 to be perfectly sufficient for P-M cooling purposes. I played with more clamping force, with no improvement in temps. My thinking is "why apply more force than necessary to an unprotected CPU die?"

More info on this can be found here, with this comment being particularly germane to this current post:

In his Pentium M motherboard writeup, Ralfie wrote: I placed the (Zalman 7000) heatsink on top of the CPU and started tightening the two Zalman mounting screws, paying special attention to the force required. As the screws were getting close to bottoming out, I could feel that the tension on the CPU was definitely less than if it had been a P4. It seemed to have plenty of tension when the screws were all the way in. I wasn't able to rock the heatsink, although I could twist it a bit. I decided to fire it up and watch the temps. If something didn't seem right, I'd make some shims to place on top of the Zalman mounting arms to apply more pressure to the CPU. The idle temp stayed stable at only a few degrees over ambient, and didn't change with extra downward pressure on the heatsink. I declared the mounting a success and proceeded with thermal testing.

Of course, as always: YMMV, IALAL, etc!

Edwood · Post by **Edwood** » Fri Jul 01, 2005 10:18 am

mco_chris wrote:I tried the Thermalright XP-120, Swittech MCX478-V, and the Scythe NCU-1000 and NCU-2000 heatsinks and they did not work on this board.

Why exactly didn't the XP-120 not fit? Were there capacitors or something that the XP-120 itself was hitting?

I couldn't use the supplied back plate and retention bracket that came with the XP-90C. Due to electronic components on the board and the angled CPU, they don't fit. There's a big capactior under the CPU that prevents attaching a solid base plate there.

Looks more like a diode, but it could be a tantalum cap. But I'm confused. Can't you just use the existing P4 rentention bracket? Does the XP-90C have through hole mounting?

*EDIT, nevermind. Answered in this thread. http://forums.silentpcreview.com/viewto ... 813#192813

-Ed

Edwood · Post by **Edwood** » Fri Jul 01, 2005 10:24 am

Which Heat sink would be better for fanless cooling? (there will still be a case fan.)

Alpha PAL8952 P4 heatsink or Zalman 7000?

I plan to use an Aspire X-PACK mATX case probably.

-Ed

Post by **Ralf Hutter** » Sat Jul 02, 2005 4:26 am

Edwood wrote:Which Heat sink would be better for fanless cooling? (there will still be a case fan.)

Alpha PAL8952 P4 heatsink or Zalman 7000?

I plan to use an Aspire X-PACK mATX case probably.

-Ed

Zalman 7000. The tightly packed pins of the Alpha aren't too condusive to the type of airflow needed for passive cooling.

Edwood · Post by **Edwood** » Sun Jul 03, 2005 11:27 pm

That's good news for me considering the Zalman 7000 is much easier to find.

-Ed

slipperyskip · Post by **slipperyskip** » Tue Jul 05, 2005 1:12 pm

This looks interesting:

http://www.microcoolsystems.it/inglese/homepage.html

Post by **Ralf Hutter** » Wed Jul 06, 2005 5:17 am

slipperyskip wrote:This looks interesting:

http://www.microcoolsystems.it/inglese/homepage.html

Interesting if you want a noisy cooling solution perhaps.

Why anyone would choose run a couple of noisy 40mm fans when there are much quieter, better performing alternatives is way beyond me. And why anyone would add active cooling to a northbridge, if they are building a quiet PC, is also very puzzling.

slipperyskip · Post by **slipperyskip** » Wed Jul 06, 2005 6:45 am

They claim 14 dB.

Thanks for reminding me why I don't like to participate in these forums.

Post by **Ralf Hutter** » Thu Jul 07, 2005 3:06 am

slipperyskip wrote:They claim 14 dB..

So do Thermaltake and SilenX, but they both place their microphones about 30 feet away from the noise source. Until a reputable source verifies that 14dB measurement at one meter, I'll remain skeptical.

slipperyskip wrote:Thanks for reminding me why I don't like to participate in these forums.

Sorry you feel that way. If you don't want to participate, that's certainly OK, but even as a lurker, an occasional perusal of the SPCR reviews and forums will keep you up to speed on issues like active northbridge cooling, the noise signature of 40mm fans and the extremely low cooling requirements of Pentium M systems. Apparently that's something the folks at Microcool Systems haven't done too much of.

slipperyskip · Post by **slipperyskip** » Thu Jul 07, 2005 11:48 am

Ralf Hutter wrote: will keep you up to speed on issues like active Northbridge cooling, the noise signature of 40mm fans and the extremely low cooling requirements of Pentium M systems.

I don't need to be "kept up to speed" on these issues. I am on the front line.

I can almost guarantee that no one on these forums had ever heard of the Microcool 855 cooling solution. I thought I would share this with your readers. I did not endorse it as the ultimate solution, just that it was interesting.

Northbridges get hotter and fans get quieter. Dismissing new ideas without due consideration is something you can practice when you are old and narrow-minded. That kind of thinking is not the basis for good engineering or good journalism.

Jeffrey Stephenson
http://slipperyskip.com/

Post by **Ralf Hutter** » Fri Jul 08, 2005 5:08 am

slipperyskip wrote: I can almost guarantee that no one on these forums had ever heard of the Microcool 855 cooling solution.

It was discussed here at SPCR two years ago. At that time, it was deemed unnecessary for a non-OCed system, and not a good idea for a system that you're trying to silence. Those remarks still apply 100% to the Pentium M boards that are available today.

NBs are generally rated to 100°C by Intel so added cooling will rarely be necessary, unless perhaps you're OCing the snot out of it. My guess is that Microcool is marketing that product to the wackos that are running their DFI Pentium M boards extremely overclocked to 275-300FSB. At those speeds, the NB may need additional cooling, but certainly doesn't at it's default 200Mhz FSB.

slipperyskip wrote:

Northbridges get hotter

Not on Pentium M boards.

chiccoweb · Post by **chiccoweb** » Sat Jul 09, 2005 11:36 pm

slipperyskip wrote:This looks interesting:

http://www.microcoolsystems.it/inglese/homepage.html

I dont't want to discuss here if the active cooling is worth or not on Pentium M systems, but I have the Microcool CoolSystem 855 inside my every day use PC and I can garantee you that the two fans are so noiseless that HDD and DVD are louder. If anyone can read Italian or could stand automatic translation I suggest to read this review:

http://www.hwupgrade.it/articoli/cpu/1317/index.html