Why a SHIM?

skimzzz

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I have a socket a thunderbird and I bought a nice copper HSF for it to keep it happy. I notice they have things called SHIMS for about $10. What are they supposed to do and are they worth it?

thanks
 
They apparently reinforce the edges of the chip around the die so when attaching a heatsink they're less likely to crack or snap. Never tried one.

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knowan

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camieabz is right. It's to help protect the core when installing a heatsink. It doesn't add any to the cooling efficiency, and may actually decrease efficiency a bit due to blocked airflow. It's not really necessary, but if you're not comfortable with the idea of possibly breaking your CPU due to incorrect installation of the heatsink, then by all means get one.

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funkdog

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Keep in mind that you can acutally damage or even fry your CPU when using shims. If you are comfortable installing Heatsinks then you don't need one. Some shims have been know to be too thick and actually prevent good die/heatsink contact, increasing cpu temps, and sometimes raising the heatsink enough to fry the chip.

Again I would suggest to anyone who is mildly comfortable installing heatsinks that a shim is not necessary.

<b>"These are my thoughts, your mileage may vary."
 

HonestJhon

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they dont only protect it during installation and removal of the heatsink, they also protect it during transport...so if you are using an amd, and move your computer a lot, then a shim is a good idea...just because of the possible jarring that a computer can take in transport.
i am thinking about getting one...just because i move my comp around a bit...like luggin' it up and down the stairs...and to other people's houses...and if i plan on going to a lan party...then it would be a definate good idea...and if you get a good quality shim, which is around 10 bucks...then i doubt that it will raise the hsf at all, and i doubt that they will leave the metal where the shim is going to contact the l1 bridges, and other components on the cpu...
you should be safe, as long as you make sure that it isnt touching any of the components on top of the cpu...and that it is just touching either the pcb (on athlon xp's) or the ceramic on the regular athlons and the athlon mp's....
you COULD make your own shim....but i dunno if you would want to risk that...
also, before you buy the shim, make sure that it isnt bent, and that it is free from burrs...but then again, if it is a good quality one, it wont have burrs, or be very bent..but check it just because you are conscious of things like having to replace the cpu because you were too lazy to check the shim, and the hsf was raised a bit...and fried the cpu, or the burr touched something on the cpu that it shouldnt have... ;)

-DAvid

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HonestJhon

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mah bad.....
i dunno if they make shims that work on the xp...so you just have to be brave....heh
sorry for the mis-information....

-DAvid

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funkdog

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They do now make shims for the XP. I still think all shims are good for are to cash in on the "False" crushed Athlon craze that the friggin Orb's created.

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HonestJhon

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false??????
i have seen them!
without the orb!!!!!!!!
we are talking just the computer got bumped, and crushed the core...it is made out of silicon, which is like glass........which shatters easily.
there is a lot of pressure on the core, to make good contact with the heatsink, and when you bump it, and the hsf jostles and gets at an angle, it puts the pressure on one side...which is most likely going to crush it.
now sure, it takes a big bump, but if you move the comp a lot...then yo are likely to bup it hard on accident...like moving it into your car or something.
also, if you take the hsf off a lot, then you are likely to crush it, like if you slip, and hit the hsf, adding a lot of pressure at one instant.
a crushed core can happen to anyone...and a shim will most likely prevent it.

-DAvid

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peteb

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I think, as you have said, it all depends on circumstance.

If your system is mobile, the shim will add value. In some cases you could also describe them as training wheels, aids to cpu installation.

There is risk in using and not using them. If you remove your HS a lot, there is added risk that the shim is mis-alligned and causes an issue, just as there is you breaking the cpu with the HS.

Just weigh up the pros and cons of both situations.

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HonestJhon

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i am thinking about getting one because how mobile my computer has become...
with my old k6-2 it was fine..those had the heatspreader on them...and that would protect the core, so i think i am going to be looking into a shim...
especially if i upgrade to an xp, because i would definately kick myself if i cracked it.
my athlon 900 has survived moving around, but i am still scared when i move it...
every time i put it in a car, i tell the person driving t otake it easy...especially on the bumps...
some may say that i am overreacting, but what i say to them is that if i follow the way they would take care of it, and if they are driving, i tell them that if the core gets cracked, then they can buy me a new one...and they immediately choose to take it easy...hehe

-DAvid

-Live, Learn, then build your own computer!-
 

svol

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Does anybody of you think that a shim will help lowering the temp if you use a Peltier/Watercooling combination system. The temps are then between 0 and 20 C. I think it can help transport heat from the CPU to the peltier and waterbloc

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peteb

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No, a properly installed shim will not make contact with the heatsink/waterblock/peltier cold plate.

Shims will not aid in cooling, their sole function is to add protection against core crushing.

If the shim is touching the cooling block with any pressure, it means that the cooling block <b>cannot</b> be making optimal contact with the cpu...

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HonestJhon

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i thought it was supposed to be the same thickness as the core, so that it would prevent the crushing...if it isnt, then how the hell is it going to protect the core??????
i dont understand...
if anything, you would want it just BARELY thinner.
otherwise, the hsf would be able to move enough the chip off the corner of the core.....
which is the thing you are trying to avoid!

-DAvid

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peteb

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If it were the same thickness, then the pressure applied from the heatsink to the core (by the clip) would dramatically reduce (given the same clip) as the surface area of the pressure would be much greater for the same force. This would result in poor thermal connection and overheating.

The shim must, as you say, be just thinner than the core. It must be perfectly flat and there must be nothing on or under it, else your cpu will overheat. It must not be too thin, else a tilting heatsink will not hit it before it has rubbed off the die edge...

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HonestJhon

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well, then what i have to say is "PEOPLE, MAKE SURE THAT YOU BUY A QUALITY HEATSINK, AND EXAMINE IT BEFORE INSTALLING!!!!"
those are some close tolerances...and i know what you are talking about, the pressure needed for good thermal contact...but the thing is, once the thing is on, there is no way to tell if it is too thick or thin, until something happens...
well, maybe not...thinking about it, if you have the cpu, with the shim on it, sitting eye level, you would maybe be able to tell if the shim is just barely thinner than the core.
i will have to try it if i buy one.
see if i can tell.
because it would sure suck to have temps rise due to the shim, and it would suck even more if the shim wasnt doing its job, and the heatsink was rocking all over the place, crushing the core!

-DAvid

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svol

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Why are they made from copper/silver (mine is copper whith some very thin silver around it, the shop didn't have others) then, they only will be more expensive.

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peteb

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yes - they will be more expensive. so why do you think they do it? so they can charge more perhaps? Also, those metals are softer, and so easier to punch and work.



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svol

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I think they do it because they think it's for better cooling. Maybe after all it's really beter for cooling if you place it right and make use of Arctic Silver. I still think it can help cooling down the surface of the CPU.
But you're right about the part that the core has to make good contact with the heatsink.

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HonestJhon

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i dont know about a shim reducing the temps of the cpu....
i dont think that it will help cooling at all...if anything it would stop the air flow under the hsf, and enclose the core, causing some heatup.....
but i i could be wrong...
maybe the softer metals is so that if it DOES get bent a little, then it will be easier to return to the original flatness....r maybe so that it will give a little, so that the hsf can make contact with the core better.

-DAvid

-Live, Learn, then build your own computer!-
 

svol

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If you are using an peltierwith watercooling the area around the cpu will be isolated so you won't have any airflow.
Maybe if you use Arctic Silver to let your shim make contact with the coldplate it can enlarge the area which can be cooled and will conduct heat from the cpu's surface to the heatsink. You can cover the L bridges with something non-conducting to be completely sure it don't shorts (although the shim is designed to don't touch the bridges, some Arctic Silver can).

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HonestJhon

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i dont know man....i am going to have to try it myself, or if someone out there is willing to test it, like give "NO SHIM TEMPS",and "AS2& SHIM TEMPS", then it would be helpful.
see if it actually helps the temps.
it might, i am not doubting that, but i always thought that the air circulating under the hsf helped a bit with cooling.
the reason that it wouldnt matter much with water cooling, and a peltier is because those cool WAYYYY better than air cooling, and because of the problem of condensation, there would be no way to see if the air would help.
i wonder if amd will start recommending shims...hehe....

-DAvid

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svol

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I think I will test it if my watercooling is completed and I have received my peltier.
I will post all the interesting things that I discover on THGC and probably make a small website about it.

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HonestJhon

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well lookie here...
i found something i thought was pretty interesting..
sorry to bring this old thread back, but i had to, because it is fitting...
<A HREF="http://www.unique-hardware.co.uk/article.asp?art=dtstweakmonster&Page=1" target="_new">http://www.unique-hardware.co.uk/article.asp?art=dtstweakmonster&Page=1</A>
very odd, but the shim took 1*C off the idle and full load temps...at least the DTS 440 did.
very odd..
but it SORTA makes sense since heat <i>is</i> transferred to the ceramic package.
what would be interesting is to have them test it on an xp, since the organic surface might not transfer the heat in the same way.
but i just thought it was interesting. :smile:


-DAvid

-Live, Learn, then build your own computer!-
 

svol

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Cool... I have a shim that looks like the DTS440 so in theory I will get lower temps.
I can't wait till its vacation, then I finally can complete my watercooling system and test it myself.

My case has so many fans that it hovers above the ground :eek: .