Risk overclocking?

[mof]

I've got:

AMD PhenomII x6 1090t @3.2 GHz
HD5850 Crossfire
2x2GB DDR3 RAM (Corsair xms3 1333MHz)
Gigabyte 890fxa ud5 motherboard
Hitachi Deskstar 3TB 7K3000 SATA III Hard Drive
http://www.corsair.com/tx650w.html
Max Load: +3.3v=24A, +5V=30A, +12V=52A, -12V=.8A, +5VSB=3A
Corsair TX650 Watt PSU

So I think I'm already pushing my PSU to its limit.
Would overclocking my CPU use enough extra power that it is likely to go over the upper limit of my PSU?

Also would it be safe to overclock with the stock cooler?

 

[RJC]

Your system at full load would be pulling around 400w from the mains.

I used to use 5850 crossfire with a overclocked i7 920 cpu @ 4ghz and custom water cooling and I would pull 430w from the mains with Prime & 3D Win mark running.

 

[mof]

Thanks RJC.
So there's no worry of using too much power.
What about the max load on the 12v rail? For my PSU its 52A and according to this website http://www.guru3d.com/article/radeon-hd-5850-review-crossfire/9 you really need 55-60A for 5850 crossfire. Although they may have assumed that the rest of your system is using a lot of power.

Also, assuming it's safe power-wise, is it safe to overclock with stock cooler or will the cpu overheat?

 

[RJC]

Your PSU will be fine

You would be able to overclock with the stock cooler but your system would probably end up noisy and only a small over clock would be achieved, If you have the budget I would invest in a better cooler.

 

[mof]

I'm not so bothered about noise since my system is already really loud when I play games.
I just played Starcraft 2 to test the temps. and the core was getting up to 64c and supposedly it shouldn't ever go over 62 and this was with the default clock speed.
I don't think I'll try anything without a better cooler.

EDIT.
After thoroughly cleaning out all the dust in my case, especially around the CPU, it's now idling at about 30c and 48c on full load. Quite a difference.