Suitable thermal compound for GPU...

[PowerPie5000]

I've just bought a 'His Radeon 6850 IceQ X Turbo' off ebay to replace my brothers old GPU. The card i ordered has been used in an online review and the reviewer used silver based 'Akasa 450' thermal compound when putting the coooler back on... I'm a bit worried as there are quite a few tiny components surrounding the GPU die (very close) and i don't want the silver based compound to start getting runny and spill over these components when it heats up (as it's conductive).

Anyway the only other quality thermal compounds i have on hand are 'Arctic MX-4' and 'Shin Etsu X23'.... Which one of these would be more suitable for a GPU? Can any CPU thermal compound be used with GPU's or do i need one specifically meant for it?

[kalniel]

Just get some generic silicon or ceramic based thermal grease.

[shaithis]

More important then the make of compound/paste is how much of it you use.

I cannot stress enough that less is more......

[kalniel]

Indeed. If you only need a grain of rice sized bit for a CPU IHS, imagine how much less you need for a GPU sized chip.

[CAT-THE-FIFTH]

I tend to use more viscous thermal compounds for GPUs due to their vertical orientation.

The Shin Etsu thermal compound does work quite well from my own experience but is a pain to spread thinly. Noctua NHT1 is similar and IMHO works reasonably well.

If you want the easiest thermal compound to apply thinly on a CPU I would get this:

http://www.overclockers.co.uk/showpr...odid=TH-000-ZA

[PowerPie5000]

I tend to use more vicious thermal compounds for GPUs due to their vertical orientation.

The Shin Etsu thermal compound does work quite well from my own experience but is a pain to spread thinly. Noctua NHT1 is similar and IMHO works reasonably well.

If you want the easiest thermal compound to apply thinly on a CPU I would get this:

http://www.overclockers.co.uk/showpr...odid=TH-000-ZA

I was leaning more towards Shin Etsu due to it's viscosity... It can be a bugger to spread but i put the syringe in a sealed sandwich bag and heat it up in hot water first.

I'm sure that Zalman stuff is the same i got with a copper Zalman HSF a couple of years back. It was ok but my old Q6600 at the time did better with the Arctic MX stuff (MX-2 i think)... And i remember the Zalman stuff being quite runny! I know not to use too much compound and i prefer to spread instead of leaving a tiny blob in the middle.

[CAT-THE-FIFTH]

Now edited my last post to say "viscous" instead of "vicious".

Coollaboratory Liquid Pro,was what you can call "vicious" thermal compound!!

[PowerPie5000]

Now edited my last post to say "viscous" instead of "vicious".

Coollaboratory Liquid Pro,was what you can call "vicious" thermal compound!!

I tried that stuff once and never again! It may yield good temps but it's the absolute worst stuff to work with! It even came in a dangerous looking hypodermic syringe complete with needle

[PowerPie5000]

I received the 'HIS Radeon 6850' today but might have to return it... After only a minute of playing BFBC2 it hit 102C and the fan went crazy . It seems to idle at around 50-55C! My 'XFX Radeon 6870 BE' idles at just over 30C and goes upto around 65C under load, and it's a faster and more power hungry card!

After inspecting the card i can see the cooler doesn't seem to be sitting perfectly flat against the GPU die (i can see this through the gap)... I've emailed the seller (who is also a reviewer for another website) and have asked if i should realign the cooler and apply some Shin Etsu X23 or just return it. I won't touch it unitil he's replied.

Good thing i tested it before driving 5 hours to my brothers house!

[dfour]

I have used artic silver ceramiq and icdiamond 24 on mine with ic being the hardest to work with unless you heat it up ass its very solid otherwise but it dropped 6 degrees on idle and load over the stock paste on my 6950.

[pooley]

Any cpu thermal compound can be used on gpu, same principal.

You can use the Arctic MX-4 you have, it a quality TIM that is metal-free and non-electrically conductive.

[PowerPie5000]

I've sent the seller a couple of screenshots of the temps i'm getting... I didn't let them get as high this time in fear of blowing the card!

What do people think of these pics...










I'm pretty sure it's all down to the cooler not being seated properly.... Does anyone know what GPU temps 1 & 2 refer to in GPU-Z? They seem very high and i'm thinking maybe Shader and mem temps?

[dfour]

looking at your pictures those gaps are not part of the heatsink that connects to th chip. Thats part of the cooler that is bolted down. The green piece is the total wodth of the gpu. If you look at your first picture you will see that the actual chip is also narrower than the green substrate.

This doesnt mean that it might be a good idea to clean of the old gloop and add some fresh stuff.

guru3d got 32 idle and 59 load temps
Tech powerup got 44 idle 66 load and 67 oc

Yours do look high.

[PowerPie5000]

looking at your pictures those gaps are not part of the heatsink that connects to th chip. Thats part of the cooler that is bolted down. The green piece is the total wodth of the gpu. If you look at your first picture you will see that the actual chip is also narrower than the green substrate.

This doesnt mean that it might be a good idea to clean of the old gloop and add some fresh stuff.

guru3d got 32 idle and 59 load temps
Tech powerup got 44 idle 66 load and 67 oc

Yours do look high.

The whole cooler is slanted... To me it looks a bit buckled. Those metal bolts are part of the coolers flat base which covers the GPU die, you can see the gap difference even widens along the top of the GPU substrate/die... You may not be able to tell from the photos but the cooler was not sitting flat/flush on top of the GPU. Even the screws on the back were sticking out at different lengths! I of course decided not to touch it in the end and just sent it back for a refund.

Hexus also got 32C idle and a maximum of 64C under full load using Furmark... Anyway, it doesn't matter now as i've sent the card back and i should get a full refund as testing will conclude what i've found unless the seller tries to pull a fast one... Can never tell with eBay these days! Thats why i took pictures, screenshots and even emailed the seller some proof, but he still said i'll only get a refund if his tests match my results (which they should).

The guy i bought the card from did a full review of it and only let me know it had been dismantled and overclocked AFTER i had paid for it! He assured me it was in full working order so i thought there would be nothing to worry about... I think the cooler on the card has been borked ever since 'HIS' sent it to him as his temps are higher than any other review i've read (obviously taken before he pulled it apart as the temps on the same card are much higher now!):

http://benchmarkreviews.com/index.ph...&limitstart=14

The card i bought was the one actually used in the review linked above.

EDIT:... If you look closely at the 2nd GPU photo, it even looks like the GPU substrate is slightly uneven (i think the whole thing must be warped!).

[CivilDrone]

Would have to agree with pooley on the paste, although highest i've seen is MX3 and was gonna recommend that, scan have them. cpu, gpu, all works