AS2 + superglue
I've done this for my gpu and video memory. You have to be careful not to use too much glue or you'll never get it off again in one piece. Also, if you use AS or any other electrically conductive paste on your video ram, use only a little. If that stuff leaks out the sides and connects the legs of the memory together electrically, say goodbye to your grafx card. Or get out the alcohol and Q-tips and pray to the OC gods for mercy.
I spread the AS thin over the chip surface, leaving 1mm or 2mm clearance around the edge, for squish room. Also, leave 2 opposing corners non-gooped, just enough space for a drop of superglue is fine. You'll need to press down when putting the sink on, and that's when the thing is gonna try to slide around and get goop everywhere.
However, I do not recommend this method unless you have a steady hand and are prepared for the consequnces should you botch it. Artic Alumina would be safer, even the non-epoxy AA would be better for this superglue method.