Air cooling for i5 overclocking

[Adokaum]

I'm planning to build myself a new system with the following specs

i5 2500k
HAF 912 (Front n Top 200mm CM Megaflow fans)
Corsair 2x4gb XMS3 1333mhz
MSI P67A-G45
BeQuiet 530w Pure Power
MSI GTX 560ti Twin FrozR II

Any alternatives to these components are welcome of course.


Anyway back on topic.
I want to overclock that i5 to 4.5-4.7ghz and im trying to find the best budget solution in keeping that around mid 60's or lower on max load. Being a low temp whore on a budget doesn't help

I've been looking at Corsair A50, Hyper 212+ and Gelid Tranquilo. (Using Arctic Silver 5 paste) Which of these or other CPU heatsinks would be best to achieve my goal? Looking to replace the stock fans on the heatsinks as well, so any recommendations on reasonably priced fans that will increase performance over stock? (Not too bothered by noise but I'd prefer a quieter fan. I currently have 4 Yate-Loon medium fans installed and I wouldn't want fans that are louder than those.) Also considering a push/pull configuration.

Since i'll be using the HAF 912 with a 200mm fan at the top, is it better to have the heatsink positioned so the fan is blowing air out through the top? Or the standard through the back exhaust? I'm guessing exhaust through the back position will be better as the heat generated from the PSU and GPU below that will rise and the warm air sucked through the CPU fan. My average room temp is usually 19-21C.

Looking forward to some input. Cheers

 

[AlfBaxter]

I have a Corsair A50 and can get my 2500K to 4.4GHz without going much over 60C under load. I do have a nice chip though, as I have it set to that the full load VCore is arounf 1.16V (VCore in BIOS is at 1.25 I think), which isn't much. If your chip needs more voltage to get up to 4.5-4.7, which it probably will, then your temperatures will probably be 70C or above. I think the A50 is good on a budget, but has pretty limited OCing potential.