My 3.3 line are also low 3.18-3.2 V, but still that does not mean I can't run my ddr at 200+
I'm just saying the problem could very well be somewhere else, rebooting also doesn't necessry means bad psu, turn auto restart in window system properties and it will very likely be BSOD that you couldn't see, and with my experience that was always the problem with memory or cpu overclocked or set up wrongly. PSU could be the problem if your Vcore fluctuate like crazy and if sometimes drop to low that mean cpu didn't get enough juice and it crashed. My 5V line was as low as 4.4V but my cpu was still stable and the problem wasn't in bad PSU but bad atx plug conection, so it got hoter and hoter until I didn't check that out and find out the conector is burned.
To remenise a little :



And here my new made 1mm copper wire plugs:


No problem from then on, same el-cheapo PSU that can easily run even my most overclocked cpu.