whats the cheapest watercooling set to overclock i7 920 D0 to 4.2GHZ?

If you want only WC for the processor i'd say Corsair H50 or the H70.

Closed circuit, zero maintenance, pre-filled...

You just need to clean the dust from it.

is it stable at 4.2ghz?

I suggest you dont get water cooling... get a high end air cooling and you can still reach 4.2GHz.

I can attest to my water cooling setup leaking all over my Nvidia GeForce GTX9800 and frying it. I stick to air cooling now.

in that case what air cooling do you suggest Talon95?

Noctua tends to make the best air cooling, especially combined with Arctic Silver thermal paste.

http://www.youtube.com/watch?v=DQxw9Sx1-Uk



Lot's of people are happy with the H50s, saw lots of reviews where the H50 beats the TRUE 120, for example, and the TRUE 120 it's one of the best , high end aircooling system.

Plus the video should be enough. =)

I got the H50 and VERY happy with it!

I would not recommend that you get a cheap water cooling system as they are prone to leak, which you could imagine could be really bad.

My advice considering the question, cheapest...
Get an H50 as Balzak says... push/pull fan system, i have a 920 OC to 4.2 and its fine, about 55c most of the time... good system, the H70 is more expensive and has a better design but doesn't cool so much more than the H50 by the looks of things.

Funny that the OP also asked how to build the cheapest possible system that could play Crysis at high res max settings... Somehow I think he's just a troll with an IQ slightly higher than mud.