i was reading some sites and they were saying water cooling may not improve overclock, i was wondering if this is true, also i have a 9800 xt and the heatsink is not very good if i put a water block on it will i be able to obtain a high overclock?
Well it is true, as the only thing water cooling does is keep the CPU at a lower temperature meaning it can be overclocked further, due to not going too hot, but if you hit your maximum overclock your system can handle on air, than water cooling will not mean it can ovrclock further.
Well what is the temperature of the GPU? and the shut off temperature? For the GPU you could get a artic cooler GPU heatsink.
watercooling effects the GPU temps WAY more than the CPU which easily allow for much higher OCs....with my 6800GT I wasn't too excited about running it at ultra speeds, 400/1100 because it'd get close to 90C...with water cooling I could run it 433/1185 and it wouldn't go above 52C....that wouldn't be possible with a heatsink unless it was a ridiculously good one....the NV Silencer might be able to achieve that.
Idle and load temps with water cooling are only like 5C though whereas with air, even a good one is generally 10C+