I use as5 on the center with a dab of superglue on the corners. Removeable and excellent transfer.
I would not recommend thermal paste as an alternative myself because it can run onto the main PCB and can cause shorts which will fry your card. The superglue trick does work as Kayin said though, just a tiny drop on 2 diagonal corners will hold the sink flat for you. If it needs removing just twist the sink and it should pop right off. I have done it once before myself and used a needle to dab on the glue. You could also use the end of a staple or a paperclip.
Project: Elegant-Li *NEW*
Project: Alpha FINISHED
Project: LEXA Revival FINISHED
Project: LEXA FINISHED Bit-Tech MOTM Nominee October 08
I can't imagine AS5 running anywhere fast but I will keep all this in mind and maybe try it this weekend.
If thermal grease shorting out the card worries you just go for the ones with graphite instead of metal in them.
Projects: RGB Tower - Custom CPU water block
-TheOatmealWatching someone else use your computer is like watching a drunk orangutan solve a rubix cube. They have no idea what they're doing and you just wish they'd hand you the damn thing so you can do it yourself.
Arctic Silver Thermal Adhesive (Review at Overclocker Cafe)
3M (expensive, maybe the best)
Parker Chomerics THERMATTACH T404, T405, T405-R and T412 Thermal Tapes (sold by the roll, expensive, but you can Request a Sample)
And of course there's always the Radio Shack stuff; cheap, quick, and dirty. Better than nothing.
Side note - I'll admit that Kayin's trick is something I've never tried before, but I wouldn't personally go for SuperGlue (cyanoacrylate-based) adhesives, I'd try a few little dabs of common potting compound (epoxy resin) because it adheres well enough, it's typically engineered with minimal thermal interface/expansion considerations in mind (it's specially made for electronic applications), and it's probably a helluva lot easier to remove with chemical solvents that don't do (much) damage to PCBs.
My mind says Technic, but my body says Duplo.
The cyanoacrylate is meant to only be dabbed at the corners-I've never had a ramsink fall off that way, and since the majority of the bond is TIM, it seems to work very well.
The 3M stuff is excellent, but it costs an arm, a leg, and a more unmentionable part.
Kayin i seem to remember you have some TIM that needs tested what is the viscosity of that stuff haha? I am just shooting around ideas because I couldnt find the super glue and been to lazy to do it honestly.
Why not just buy this?
http://cgi.ebay.com.au/Sekisui-5760-...item4aa29b8757
This is the same stuff I used on those sinks I sent you. works great. Japanese made and the auction is located in the US so shipping should be dirt cheap, only a few dollars.
Project: Elegant-Li *NEW*
Project: Alpha FINISHED
Project: LEXA Revival FINISHED
Project: LEXA FINISHED Bit-Tech MOTM Nominee October 08