i have a i5 4670k i want to overclock to a safe voltage.
msi z87-g45 gaming mobo
cooler master hyper evo 212 (air)
ok,,,well I would say start it at 1.25 volts and see how high you can get it to overclock before it is unstable. If the temps aren't bad then push it to 1.3 volts. My 4670K is sitting stable at 4.5 Ghz 1.3 volts on a hyper evo 212 right now. It runs kinda stable at 4.6 ghz, 1.35 volts, and I can't get it stable at 4.7 ghz consistently with 1.4 volts for more than an hour. 4.8 ghz, I just can't do it. I tried 1.45 volts, but I just don't feel comfortable going any higher than that.
1.35 volts? That under water? Or did the voltage max accepted by community change for haswell?
I dunno. My chip for some reason seems to run pretty cool. I don't think most haswells can run at 1.35 volts on air but mine tops out at around 70 degrees on air. But I feel like my chip would have more longevity at 1.3 volts so I keep it there. My 4670K really doesn't like to overclock above 4.5 Ghz and I really need to crank the voltage up beyond that point.
how do u know what the limit in ghz is for 1.25 volts
you don't. Its different with every chip. Thats what you need to find out yourself. I would say go for 4.4 Ghz first, and if that crashes, then drop it to 4.3 ghz. If it is stable, try 4.5 ghz. AKA this is what overclocking is. I recommend the Cinebench benchmark or Prime95 blend test to test your OC.
is 1.25 volts a safe voltage to start with
I'd start at 1.2...
Well I did.. And I have kept it there....
I am at 4.2Ghz @ 1.2v max load temp of 49c in Prime95 (24 hours of testing), this is with an all in one water cooling unit though Zalman LQ315.
I am sure I can push my chip higher at this voltage and of course I can put more volts through it as well but as I am using it as a LAN box with a 270X 4GB, these clocks are already fast enough.
My advice. 1.2volts 4.0Ghz and start from there. Gradually increase the clock rate at 1.2volts, 4.3Ghz, 4.4Ghz etc until it becomes unstable, then add a little more voltage to it to get it stable at say 4.4Ghz.
You will reach a point where your OC/CPU exceeds its voltage efficiency, 1.3v might get you 4.4Ghz but 1.4v might only get you 4.45Ghz... See what I mean? That means you would opt for the 4.4Ghz 1.3v clock.
I kinna top out at 4.2GHz @1.22v, anything above that is buggy. I think my 4670K is one of the unlucky ones, but meh, works for me. I did a fair amount of hunting for a voltage sweetspot and 1.22 was the main one.
wow that sucks....are you getting clock watchdog timeouts? I don't get any issues until I am above 4.5 ghz with a sweet spot at 1.3 volts. Although I think I got lucky with my chip.
I de-lid my CPU, have it under water, and can push 5.1GHz at 1.5v.
So. You know. Voltage.
As long as you keep it cool, up until a certain point (1.4-1.45) voltage itself wont begin to damage the CPU. Just up it as much as possible until your temperatures reach about 80C under load.
(Yes, I know Haswell goes to 100-110 C before throttling, but when overclocking, you want to be safe)