there are 2 kinds of water cooling hd systems i've seen. one's a cold plate design were you slap big ol waterblocks on the sides of the hd and it cools it (not a fan of this method). i've also seen what looks like an I-V pouch (like in the hospital) but your HD sits in it and water flows over it. they make them for your ram too. just little sleeves that go over your parts... they seem like they would be the shiznit.