@sergiu - I don't agree on the pads! While you are correct the thermal transmission of many pad materials are not as transmissive as thermal paste, that’s not the real issue!
Thermal paste is intended to be filler to fill in the micro pores of the heat sink and the chip cover so more heat can be transferred. Keep in mind the thinner the coating the better!
Here the pads fill a bigger void between the VRAM chips and the GPU heat sink. Thermal paste is not designed to fill this gap and is less transmissive at these thicknesses! So you can’t do a Apples to Apple comparison as each serves a different role.
So please use pads where they are required on VRAM chips! Use paste on CPU's and GPU's
Now here’s the bump! There is a gapping thermal paste which is CR#P! Apple was one of the first to use it and many manufactures have followed. Please! Don't try using the CPU/GPU paste when you see this, replace it with pads! FYI - The pad is more transmissive than this junk paste!
You should use a gap gage to measure the space dry fitting the heat sink to pick the correct pad size for your VRAM chips as different makers chips often need different sizes.
Here's something new which I've been thinking on giving a try: Graphite Thermal Pad