Personally, I would recommend using the Arctic Silver 5 on the GPU, and use the included silicone paste for the memory. Use the paste for the memory because it doesn't conduct electricity, which AS5 can, and if some goos off the memory, you can pretty much kiss your video card goodbye. This doesn't happen with the silicone paste, so thats why I say to use it on the memory. It is safe to use the Arctic Silver on the GPU, especially if you know how to use it correctly, as you most likely won't have any problems, unless of course you apply the whole tube .