5850 wattage

So I looked up the reference wattage of the 5850 and it says it's 151W. I plan on overclocking once I put it under water, but I'm not sure how much the wattage will go up. Would rounding it up to 200W be a good approximation for the heat output of this card overclocked? I'm fine if it's grossly over, but I would like to know have to worry about it being too low, which I think is quiet unlikely, but better safe than sorry.

Note, I will be pairing this with my i7-3770k and overclocking that as well. Most likely gonna shoot for 4.5GHz on it. Not sure if/how much I'll have to change the vcore to, but I just assumed 1.3 to get a rough estimate and using the extreme PSU calculator I got around 110W. I plan to use the new swiftech AIO cooler when it comes out and I just want to make sure I add the right amount of radiator to keep the cooling setup in the nearly silent range.

If you are going to be tweaking the voltages then 200w is a pretty safe approximation. Dependent on the scale of the overclock you are looking at about a 10-30w increase in wattage.

Well I've never overclocked before so this will be my first time. I don't really have any expectations. I just want to have some fun overclocking and learn a bit in the process. And you know, any gains in performance would be a nice bonus.

Thanks for the insight. I'm gonna do some calculations for cooling then.