Help with 3570K OC

[uberness]

I have a i5-3570K with MSI Z77A-G45 motherboard. I am having trouble finding a stable OC past 4.2GHz at 1.2V core. I can push it to 4.4GHz at 1.2V and run prime95 or IntelBurnTest for 8 hours straight without problem. But once or twice in a week I'll just be browsing or just moving my mouse around and the system will freeze.

I can in increase voltage to 1.3V and still have the same problem. All stress testing passes but occasionally the PC will freeze when it's just idling. 4.2GHz at 1.2V is the only setting that is truly stable.

Is it just my chip's limitation or is there something I can try to achieve better OC? I just find it strange that I can pass all stress testing programs but not the "casual use for a few days" test...

[rommelrommel]

Have you tried to rule other things out, memory, etc? Are you running offset, turbo, anything like that? 4.2 seems to generally be pretty easily achievable but there are no guarantees of course. What are your temps like? Have a good power supply? More info please.

[uberness]

My temps are 30 idle and 65-75 running prime95. I turn off all power management features. I use Mushkin Blackline 8gb 1.5v. RAM is not overclocked. My PSU is Corsair HX620 from my old system. Maybe the PSU is the problem since it's 4+ years old and runs 24/7?

Coincidentally 4.2GHz at 1.2v is what MSI OC Genie sets if I use it to automatically overclock my CPU. I thought these automatic OC programs are usually very conservative and I should be able to achieve better results.

[GT7R]

Sounds to me as if it's a memory problem. Just boot-run memtest for any case.