Thought I’d post my experience on using Ali Express PTM7950 and Upsiren 1mm 21W Thermal Pads on Vram. Before PTM7950 with stock paste the gpu would be at 2814MHZ GPU and 2514MHZ Memory and Hotspot would max out at about 90-93C running Time Spy Default.
After at 2914MHZ GPU and 2700MHZ Memory with 24C Ambient at 3 Days i get 78.7C Hotspot running default Time Spy. Since then its dropped a little bit more with a screw tightening. I bought the 80x80 as it took a couple tries to get it right but think it would be easier next time. Definately put in fridge for an hour 1st as its like peeling off one of those kids tatoo transfers very thin.
7900XT after PTM7950 and Upsiren 1mm Thermal Pads on Vram bought from AliExpress
I can understand where you are coming from but i can’t say i am unhappy with my purchase. RTX 4090’s have been having alot of problems with melting power connectors and Nvidia especially where i live are considerably more expensive. I can only imagine if Nvidia had no competition from AMD you would have to sell a kidney just to play video games. Cheapest major brand 4080 in Australia is 1900$AUD/1236$US where the Merc 7900XT was 1349$AUD/878$US.