Thermal paste

[deathvirus05]

how may degrees does thermal paste reduce?

[zipdogso]

Originally Posted by deathvirus05

how may degrees does thermal paste reduce?

How long is a piece of string ?

pastes don't actually reduce the temperature at all....that is the job of the heatsink. pastes are "Thermal Interface material" TIM for short and the job of it is to transfer as much heat as possible from the hot object (CPU) to the heatsink.
They often have a value usually xx Watts/mK this is the value of thermal conductance and is the amount of watts transferred by a specific quantity of paste etc etc...(gets a bit complicated.) you generally want this figure to be as high as possible. Without checking...I believe the value of popular ones are in the region of 9w/mk. Some carbon compounds are in the region of 20w/mk.

People often quote a bar chart with different pastes using the same HSF and they list the different temps achieved with it but this only serves to illustrate the different w/mk of the pastes. The temps are not useful unless you have exactly the same setup and exactly the same ambient temps etc.

You can only attempt to calculate temperature drop when you know the thermal conductivity of your paste and the thermal resistance of your heatsink. The thermal resistance of your heatsink this quoted as xx ºC/W or more correctly in Kelvin - xx ºK/W.
When choosing heatsinks this figure wants to be as low as possible.

[WinnieThePwn]

Generally people will see a ~4-5 degree drop switching the sticky pad crap that comes with it to real Thermal Paste.

[ShrimpBrime]

Thermal paste will generate 100% contact between the cpu and cooling device. It fills the tiny places the two metal contact points of the cooler and cpu don't touch.

Many times you will find Integrated Heat Spreaders or (IHS plates) to be concave. In this scenario, the thermal paste plays a big role in contacting two surfaces.

Different types of thermal paste are used. Most commonly used in the past is AS5 (Artic Silver)

You can also "Lap" the cpu and IHS plates for better contact and minimizing the amount of thermal paste you'll use as well. This is the How to Lap guide http://forums.extremeoverclocking.co...d.php?t=314766

[ORL]

Originally Posted by ShrimpBrime

Thermal paste will generate 100% contact between the cpu and cooling device. It fills the tiny places the two metal contact points of the cooler and cpu don't touch.

Many times you will find Integrated Heat Spreaders or (IHS plates) to be concave. In this scenario, the thermal paste plays a big role in contacting two surfaces.

Different types of thermal paste are used. Most commonly used in the past is AS5 (Artic Silver)

You can also "Lap" the cpu and IHS plates for better contact and minimizing the amount of thermal paste you'll use as well. This is the How to Lap guide http://forums.extremeoverclocking.co...d.php?t=314766

Be warned... Lapping is a 100% Warranty Void, not to mention risky when in experienced. I practiced on several IHS' before attempting my costello and still managed to ruin it. Just a heads up lol

[bbplayer5]

Ive had no luck with AC5...Shin Etsu seems to make contact better and lowers temps for me considerably.

[zipdogso]

Originally Posted by bbplayer5

Ive had no luck with AC5...Shin Etsu seems to make contact better and lowers temps for me considerably.

This is a common misconception...strictly speaking your Shin Etsu did not lower temps it just increased the speed at which heat was removed from the CPU to the heatsink because it was a well applied TIM with a good thermal conductance and you were using a good heatsink....strictly speaking the heat was removed by the heatsink.

You could have Shin Etsu with a crappy heatsink and in your eyes you would say the Shin Etsu didn't lower your temps much BUT that would be wrong.....you see.

Heat always travels towards the coldest point so your heatsink draws the heat through the TIM by being colder than the CPU
...... if you put a good heatsink on crappy TIM or don't apply a good TIM properly you dont get good results because the TIM cannot transfer the heat to the heatsink fast enough.
......If you put a crappy heatsink on good TIM you don't get good results because the heatsink cant dissipate the heat and as both sides of the TIM are warm no heat is drawn through the TIM.
......If you put a good heatsink on good TIM....Whoa, now we are rolling...then it is just a case of getting a TIM with better thermal conductance.

The idea that TIM alone lowers your temps is garbage....strictly speaking. Try putting on some TIM and not bothering with a heatsink...according to you it will lower the temp......

[linuxfan2000]

You have to have it between your CPU and hsf.
Make it a thin layer and be sure it covers the whole CPU.

[901-Memphis]

Originally Posted by drdeathx

Lapping is pretty simple.

Thats exactly what i was thinking after i read that puzzling post about it being difficult.

Just need a good piece of flat glass to use when sanding and its cake.

[ORL]

I was lapping my IHS and somehow damaged the CPU. It never would work there after. I cannot say it is a risk free endeavor, Period. That is what I meant.

[901-Memphis]

The damage can come from static electricity or damaging the pins. If you are doing something like a 939 processor or something with pins sticking out, ripping an old socket out of a dead motherboard works wonders for lapping.

Its a little easier with Intel Pinless chips.

What chip did you end up killing from lapping?

[ORL]

Just a 550, nothing major was ore of an experiment than anything.

[ShrimpBrime]

Originally Posted by ORL

Just a 550, nothing major was ore of an experiment than anything.

Don't try de-lidding cpu's if you have trouble lapping lol. jk.

[ORL]

Im not saying its hard, just saying take a couple precautions lol. I made a mistake somewhere that caused the chip to fail. Crap happens, its why I bought my 720 so I am happy lol.

[901-Memphis]

I've got a few Opterons naked in the past, and its not easy working close to those tons of tiny chips surrounding the core, but i am 3/3 with no broken internals on all of the 939 chips.

Well except for the single core i zapped at around 2v v-core on the lanparty , but thats a different story.

[AlphaElite]

I will soon be building my first system by myself, (finally!). My understanding is that the thermal paste should be of the highest quality, meaning it can conduct or transfer the most heat? Also, for application, how thick? We don`t want gobs, but just a thin layer for example between the CPU and the MB? How thin is thin? Razor thin? Like butter scraped over dry toast? Thanks.

[901-Memphis]

If you are using a heatsink that has a flat base you can use a line across the core. A horizontal line across the core will end up with a solid paper thin application just like pictured in the file i attached.

Ideally you would have almost no paste there, so the smaller amount you have without having metal to metal contact is ideal.

If you have enough paste you can experiment with using less and less and keep checking your application temperatures until you teach yourself the right amount.

Remember to use 91% Iso Alcohol and something to clean both the base of the heat sink and the integrated heat spreader of the chip.

I use an old clean cotton t-shirt along with the 91% alcohol, but as long as its lint free you will be fine. Don't use a paper towel for the final pass unless its a Viva which work okay for cleaning chips.

[AlphaElite]

Thanks Memphis! Very helpful information. I`m sure once I`ve done this a few times it won`t be such a big deal. It`s just the first time off of the diving board, ya know!?!
Thumbnail was great too!