Do you know roughly what the average power draw was when you were doing the time spy extreme test?
It's obviously a VERY different setup, but, I have the 4090 FE block from watercool. I used Kingpin KPX paste (not the included Kryonaut), had roughly a 0.5gpm flow rate and my ambient was between 22-23c. Card was OC'd to around 3K/11.6K on the core/vram, max power limit etc. When I did a 30 minute loop of Port Royal 4K the highest delta peak I saw was 18c at ~515w. After 15 minutes I measured the average power draw at around 470w and the average delta was around 16c. This was all read through HW info.
Half the flow rate should nullify any advantage from the TIM. Did you measure the core temp Delta via a physical thermistor or through software ?How much of a difference is there between physical temperature monitoring and software for GPU? Even with all the different variables, it would seem like hw info would be off by quite a lot.