i've been trying to overclock my 2500k recently and it seems i cant get it to be stable unless the voltage is on auto. I'm overclocked to 4.2 right now with voltage on auto and cpu-z says it gives 1.272-1.308 voltage when the cpu is being used. I tried to set the voltage manually at 1.310 and when i run a stress test like prime 95 or intel burn test it blue screens within a few seconds of starting the test. I've bumped the voltage all the way up to 1.35 and it still isn't stable in the stress tests. which makes no since to me because it's completely stable if i leave it on auto, even though it gets less voltage when on auto. i've read that people run this cpu at 4.5 with less voltage. my temps stay in the low to mid 60's when stress testing, havent seen it get over 50 the rest of the time, idles at around 30. any help would be appreciated as i'm pretty new to overclocking.
noctua d14 cpu cooler
gigabyte z68x-ud4-b3 mother board
haf x case
kingston hyper x ram
coolermaster silent pro gold 800 watt power supply
nvidia 570 video card
windows 7 64bit OS