I have some questions about thermal pads.
Do thermal pads dry out (when) ?
Do I have to replace them when taking of the heatsink of the graphics card (they are placed at memory chips)?
Which thermal pads are good?
If you are talking about the graphic core, or the CPU, thermal Pads are generally not recommended, as some, when heated, will melt and stick, leaving residue that is REALLY hard to get off. Also, their thermal conductivity isn't the greatest.
Some thermal pads will dry out because of the material they are made out of.
BUT, if you are talking about the thermal pads on the memory chips of the GPU, you can just leave them there, as memory doesn't create as much heat as an actual core does.