Vega 64 LC hotspot sensor and its accuracy.

[PotatoVonEpicus]

Yesterday I played some games on 1440p with my undervolted Vega 64 LC ( 1650 MHz 1.1v core, 285w ). Highest core temperature reported by HWinfo was 71c and average was mostly around 65c. Hotspot temperature however was reported as 110c, which I doubt was accurate because I didn't see that affecting core clock at all.

Today I took some time to replace thermal paste and made sure there is thermal paste in the main culprit for hotspots which is groove in between core and HBM. Ran some Furmark, 320w hotspot hit 99c and I am sure it would have been higher if I let it run for longer.

So now I am wondering how accurate this sensor is, considering there was no real change after applying new thermal paste. Also hotspot can be up to 50c higher than GPU temp, which again makes no sense to me. On top of this I seen some Vega users have reported similar issues with Vega hotspot on different sites while using HWinfo.

 

[Martin]

I'm sorry but we don't have any details about accuracy of this sensor.
But it's a quite common phenomenon that accuracy of thermal sensors is best in a certain range and worse below or above it.

 

[PotatoVonEpicus]

I'm sorry but we don't have any details about accuracy of this sensor.
But it's a quite common phenomenon that accuracy of thermal sensors is best in a certain range and worse below or above it.

I see. But if sensor is reporting inaccurate and high hotspot temperatures core should throttle down and drop clock. It doesn't do that and that is the weird part for me. It's reporting high hotspot temp without taking any action to drop it down.

Also I assume it's average of multiple sensors? It's not the highest temperature on the chip, but rather average from multiple sensors arranged in the grid on the chip.

 

[Martin]

Hotspot should be the instant maximum value, but as I said - no one except a few AMD engineers has insight into the exact algorithm used in the SMU.
Temperatures can fluctuate very quickly (within milliseconds), that's why most vendors tend to prefer averaged values over a certain (short) time interval.

 

[PotatoVonEpicus]

Hotspot should be the instant maximum value, but as I said - no one except a few AMD engineers has insight into the exact algorithm used in the SMU.
Temperatures can fluctuate very quickly (within milliseconds), that's why most vendors tend to prefer averaged values over a certain (short) time interval.

I just gonna assume it's not really worth worrying about hotspot temperature with Vega. It's supposed to shutdown PC or throttle at 120c or so anyway.

Thanks for information.