Remove the GPU from the GPU heat sink.

Make sure to apply a new layer of thermal paste to the face of the GPU (the area boxed in red) before reattaching the heat sink. Our thermal paste guide makes it easy.

Before installing new thermal paste and mounting a new GPU to the GPU heat sink, use the flat end of a spudger to push the VRAM thermal goop closer together so it will better contact the VRAM when the GPU is installed.

Do not use thermal paste on the VRAM chips (the black boxes around the GPU). The VRAM chips are shorter than the GPU, and therefore need thermal pads to make contact with the cooling element. Replacing the thermal pads with paste will cause the card to overheat and can potentially ruin it.