Heatsink guide

[iisbob]

Here is a really great tutorial on heat sinks and their operation. I've come across some interesting questions in other forums ( mainly OC and gaming ) where people have asked about the proper use of/ and how they work.

Heatsinkphysics (http://firingsquad.gamers.com/guides/heatsinkphysics/default.asp)

I'm fixing to try out a new all copper one myself; intereted to see how much of a diff it makes with the athlon(s).

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iisbob
"Soap and education are not as sudden as a massacre, but they are more deadly in the long run."

"Imagination is more important than knowledge. Knowledge is limited. Imagination encircles the world." --Albert Einstein (1879-1955)

[bassvax]

Great link iisbob http://www.PCGuide.com/ubb/biggrin.gif

I spent nearly an hour there and now have bookmarked the site. I like being able to get multiple opinons/reviews on games and hardware before plunking down mega $$.

I'm dreaming of a Geforce 3 Ultra card. They sure make those things (video cards) hard to understand...I mean the name itself is confusing...for example: Elsa GLADIAC Geforce Ultra 3...Elsa=manufacturer, GLADIAC=model, Geforce Ultra 3=chipset. I say this because now I have to find out which Geforce 3 is best for me. It seems as though the Asus video card works great with my Asus A7V133 (KT133A) maybe there's a story there...I see poor performance from (friends pc) NVIDIA 32MB TNT2 M64 4xAGP running in a PIII 800 Dell System (4100) 256MB on 3D games like Rogue Spear.

I'm getting ready to build one for my kids and I'm still contemplating the mobo to use (son is a 3d gamer and starting college this month). I do know that I am sticking with AMD Athalon/T-bird though.

It's been brought up before, but I wonder if ixl would consider a Guide page-bascially just a links page with some of the best guides on the net...like this one and maybe the Kingston memory guide etc.

One last thing...thinking about utilizing the Promise controller on my board...do you think that's gonna entail a complete work over of my current setup: Win 98 SE with an IBM Deskstar 75GXP 46.1GB with 4 partitions. Would a few changes in the BIOS & DM (currently have the Promise disabled) then moving the HD to the Promise IDE channel work?

I know...I got way off topic...

Glad to have your expertise back in this game...Speaking of games...do you do any Soldier Of Fortune or UT online? If so, maybe we can hook up. Cable is great http://www.PCGuide.com/ubb/smile.gif

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Flush 'N' Forget
FE Stokes WWTP (http://www2.apex.net/users/hwuswtp)

[ranchdog]

iisbob Recently saved my meager allowance for couple weeks (thought I was missing something) and purchased a CAK38 by GlobalWin. It's the all copper version. This puppy does a bang-up job of cooling. Sits on a 1gig Athlon (MSI Mboard) and I can yank the chain pretty hard. The CPU runs at 38C - 40C. For an air-cooled unit, copper heatsinks are worth the cost. http://www.PCGuide.com/ubb/wink.gif

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......Indecision may or may not be my problem......
...... Kickin' A Rock....

[iisbob]

Did you run out of breath, bassvax?! http://www.PCGuide.com/ubb/tongue.gif LOL

I've got the Geforce3 now, love it. Can't wait to see what's around the corner ( i was using a Gigabyte board-DDR of course, then i switched over to the ECS SIS735 chipet, and it runs even smoother!), i've got a Hercules Prophet III, they're kinda rare now, i think Guillimot quit making them. http://www.PCGuide.com/ubb/frown.gif

Glad to hear of your success ranchdog, i'm looking forward to my new Athlon MP cpu! http://www.PCGuide.com/ubb/biggrin.gif I'm happy to hear such positive results about the copper heatsinks.


bassvax not to knock the TNT2 ( cause i used to have one ) but it just ain't cut out for serious gaming anymore. It was cut to run at the pci bus width ( 32bit-though there are 64bit pci boards out there ) unlike it's predecessor ( TNT ultra ) which ran at 128bit. Kinda hurt it's performance. http://www.PCGuide.com/ubb/frown.gif

I have rogue spear but hardly ever play it, i get more into Mech4 and janes WWII-and sometimes StarTrek Voyager: Elite Force ( quake for StarTrek ). Got Combat flight sim2, Independance War II, and several other games that i hardly have time to play anymore. http://www.PCGuide.com/ubb/rolleyes.gif

Between work and now returning to school, i'm lucky if i can get online anymore!

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iisbob
"Soap and education are not as sudden as a massacre, but they are more deadly in the long run."

"Imagination is more important than knowledge. Knowledge is limited. Imagination encircles the world." --Albert Einstein (1879-1955)

[This message has been edited by iisbob (edited 08-18-2001).]

[ranchdog]

Palamino ? You're breakin' my heart. The reviews have good things to say about this one. And Santa ain't due for a good spell. Let us know how you like it. The benchmarks against the T-bird were positive. Luck.

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......Indecision may or may not be my problem......
...... Kickin' A Rock....

[iisbob]

Sorry dog, it's not a Palamino-just a little revamped t-bird (specifically targeted for business platforms) but it'll do until i can get my hands on the Palamino. http://www.PCGuide.com/ubb/biggrin.gif

Go here, Athlon MP (http://www.amd.com/products/cpg/server/athlon/prodbrief.html) take a look at the brief on it.

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iisbob
"Soap and education are not as sudden as a massacre, but they are more deadly in the long run."

"Imagination is more important than knowledge. Knowledge is limited. Imagination encircles the world." --Albert Einstein (1879-1955)

[not_fred]

Glibly written article...pity it wasn't all that technically accurate. It's not all wrong, but doesn't actually give a very good understanding of the physics.

Stop here if you're easily bored by engineer-speak. Otherwise, grit your teeth & read on. A primary technical reference is at the end, if you're interested.

The definition of conduction given on the site is mistaken: is not limited to "within itself". Conduction is a heat transfer process that takes place due to contact, whether the contact is within a continguous piece of material or at a joint.

Radiation is a matter of the balance between the absorbtion of energy and its radiation, since every body wants to do both. What's important is the ratio between them, not just the value of emissivity (which is all that was treated in the article). To keep things cool radiative environment, don't absorb much, and emit a lot. That's why they DON'T wear black in the desert - they want to reflect a lot of the incoming thermal energy (with white garmets) rather than have to emit it back to the environment. Application of the right paint (such as Z93, for instance) can be a conductive insulation, but can markedly improve the radiation - it is done all the time in spacecraft design.

I do, however, agree that radiation (and therefore color) is of no consequence in the design of a CPU cooler. However, the surface roughness of the paint could have a very significant effect (paint might well be smoother than the underlying metal, which might be good or bad...we'd have to test to be sure...a little rough would increase the effective area...too rough would slow the local flow...)

Convection is actually a mixing process that introduces cool air to a hot surface. In the classic definition, it relies on gravity to boost the newly warmed air up and away from the hot surface. The warm air has to be replaced by cool air from further away. As the cool air contacts the hot surface, heat is transferred conductively. Use of a fan is sometimes referred to as "forced convection" because it transports heat the same way. What counts is the rate at which cool air is drawn into contact with the hot surface, the amount of time each molecule spends there, the temperature differential, and the specific heat of the air (water content matters).

I'm not convinced that a thick heat sink is all that bad, under the right circumstances. The increased thermal mass results in "thermal capacitance" - the speed of the heat sink's response is slower when the capacitance is higher. In other words, a massive heat sink heats up and cools off slower, all other things being equal. If the conductance is high enough (so that it won't support a large internal temperature differential) then a massive sink might work well for usage in which CPU is subject to "bursts" of energy (transients). Are our CPUs operated that way? I don't know. If the fan balances the steady-state temperature of the sink below the damage threshold temperature of the CPU, then the extra mass can help smooth out the transients, thereby decreasing the power required in the fan. We use "lumped masses" in spacecraft thermal design, too, for just that reason.

Note that PCM behaves similarly, as it melts and re-solidifies with temperature cycling. The melting process takes a lot of energy - the "latent heat". It is much more responsive (quicker acting) than the larger thermal mass, but generally has less specific capacity.

A combination of thermal mass and PCM is probably a decent compromise. That may be what lies behind AMD's opinion (as yet unsubstantiated in an engineering sense) that they prefer it to paste. The paste conducts better, but it doesn't have the fast-acting response to transients. On the other hand, the PCM won't work unless it is very, very close to the source of the heat. Local effects will end up dominating. Therefore, it needs to be distributed close to the source (lumped).

If you really get off on this stuff, try "Satellite Thermal Control Handbook" (Gilmore, ISBN 1-884989-00-4), Chapter 4 "Thermal Control Hardware". Sections 1 ("Thermal Control Finishes"), 2 ("Mounting and Interfaces"), and 8 ("PCMs and Heat Sinks").

N.B. - PCM = "Phase Change Material" - fancy wax.

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I'm only the Engineer...I have no idea how it works

[This message has been edited by not_fred (edited 09-11-2001).]