Thermal paste on GPU suitable?

[Collywobbles]

Hi all,

I have set up a water cooling loop on my rx6800 xt nitro graphics card, and at idle the heats are really good, including that of the hot spot, as soon as I put a load on the gpu though the temps rise quickly and the hotspot gets over 110 then shuts off pc (after a couple of minutes), the delta is over 40degrees between the global and hotspot temps, this tells me that there isn’t great contact with the water block, I have tried re-applying thermal paste, last method with a thin layer spread over the whole die, exactly the same issue, I am not wondering if it’s a compatibility issue with the water block and the card, maybe the die is a different size than the water block?, anyone had any experience of this and know a fix (do I need a copper shim or even a thermal pad instead of paste).

Spec is Sapphire Radeon rx6800 XT Nitro+ graphics
Water block is

Barrow AMD Radeon 6800 / 6900XT AMD, Saphire, MSI Founders Edition Graphics Card Waterblock​

Thanks in advance.

 

[Collywobbles]

It could very well be the thickness of the memory and VRM thermal pads.

Had the same issue with an Alphacool block on my RTX 4080 and it was for that reason.

In what way?, was it too thin or too thick?

 

[Collywobbles]

Thanks all, it was indeed the thermal pad thickness, replaced it all with the actual pads that come with the cooler (should have done this first!), temps are now much better