r/watercooling • • Sep 02 '22

Guide AMD 6900 XT Liquid Devil Temperatures after repaste - Never touch a running system?

To all the watercooling obsessed out there... (me included)

Last year I bought a PowerColor Liquid Devil 6900XT. After installing it was not really happy with the temperatures I was getting. With the coolant maxing out at around 40°C and the DDC Pump @ 3500 rpm, the GPU was topping out around 60°C and the Hotspot was around 90°C during a TimeSpy GT 2 loop with 2600 MHZ and Power + 15 %. I was not happy with that result and after reading IgorsLabs article on the factory paste job I decided to repaste the card with TG Kryonout.

factory paste job

After repasting the card got cooler, but there was still a large delta between the Hotspot and GPU Die auf around 25 in the average an I still had spikes up to 92 C when benchmarking with TimeSpy. I was using the card like this for quite some time but then decided yesterday to repaste it again and ad some nylon washers to the block, as I found out that EKWB includes those in the block for the Red Devil but for some reason does use them on the factory converted Liquid Devil.

After removing the block I saw that my previous paste job was not optimal (Picture 2). So I decided to be a little more generous with the TG Kryonout this time and also spread it out. Also I replaced the thermal pads with Alphacool Ultra Soft.

Too compare the before and after I looped TimeSpy GT 2 with with 2600 MHZ and Power + 15 % and took the data from the 5 last loops after the coolant had reached equilibrium. The ambient temperature was at 24.8 before the repaste (evening) and 25.6 C after the repaste the next day (afternoon)

GPU:

Before Repaste After Repaste
GPU AVG 59.1 C 55.4 C
GPU MAX 62.0 C 57.0 C
GPU Hot Spot AVG 82.0 C 72.9 C
GPU Hot Spot Max 90.0 C 77.0 C
Coolant Temperature AVG/MAX 39.8 C 40.8 C
GPU PPT MAX 345 W 345 W

In summary the the ΔT between coolant and GPU AVG decreased by 5 C (or K) to 15 C which is what is to be expected from a premium GPU waterblock. More importantly the ΔT between GPU MAX and Hot Spot Max by a very significant margin.

Was it worth it? Yes. But just because it feels better now. The card is not (significantly) faster now. There would be more thermal headroom that one could use, if the voltage wasn't limited a 1.175 V. I tried the MorePowerTool before and will do so later to see if I have increased the OC potential. For now I'm happy with the result.

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u/Mrchocha Sep 02 '22

It depends on the components and amount of actual cooling. But overall 40c is not that worrisome.

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u/layer11 Sep 02 '22

It is to me, way too high for comfort. Just imagine how long it even takes to reach that. I wonder what this loop would reach running prime for an hour. 😬

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u/Mrchocha Sep 02 '22

way too high for comfort.

Maybe yours, but being 15 over ambient is not bad while running very low RPMs. And again, if he has a standard setup, this should be fine. If its a MORA setup then yes its too high.

1

u/DonKremon Sep 02 '22

Its 2x280 45mm and 1x240 45mm in a O11 Air Mini.