Help refining overclock

[FL630]

So I think I've managed a stable overclock, but the voltage is a little higher than I'd like right now, so can anyone point me in the direction of how to make this a little more "long term friendly"?

I'm not sure I got the greatest of CPU's, I was really hoping for a lower voltage at 4.7 or in an ideal dream-world 4.8GHz. My mate got one of the magic "top 10%" CPU's so I feel hard done by not managing to match his 5GHz

Spec:
i7-4790k
Gigabyte Z97X G1 Gaming
16GB DDR3 HyperX Savage 2400mHz
Corsair H80i (temp until I install custom loop later this year)
EVGA Supernova G2 750W PSU

My BIOS changes are as follows (all terms are from my Gigabyte BIOS, naturally other brands call settings different things) :

CPU Multiplier: 40
Turbo Ratio: 47
Uncore Ratio: 40
Vcore: 1.325v
CPU VRIN External Override: 1.9v
Ring Voltage: 1.2V

K OC: Enabled
CPU PLL Selection: LCPLL
Filter PLL Level: High
CPU VRIN Loadline Calibration: Extreme
PWM Phase Control: eXm Perf.

RAM has XMP enabled and is running at 2400mHz which I'm happy with.

Temps during stress tests such as Realbench Benchmark (x5 cycles) hover around the low 70s.

I'd like to reduce my Vcore to 1.3v if possible, but I get BSOD's, could I lower it however and change any other settings to keep my required stability?

Where does one even start to make it a more efficient overclock.

Thanks,
FL630

 

[setter]

Voltage is a bit higher than average, but still safe enough. And your temps are very good. Id be happy enough with that, you've stated that any lower on vcore causes issues. And tbh that's the voltage that has the highest impact on temps but you cant lower it. Unfortunately its just the luck of the draw when purchasing a cpu as to how well it overclocks.

 

[Neil79]

CPU VRIN External Override: 1.9v <- this can go up to 2.15 safely, no higher though
Ring Voltage: 1.2V <- This can go up to 1.285, no higher
Vcore: 1.325v <- this is fine, I need 1.333v for 4.7ghz
Uncore Ratio: 40 <- try a lower uncore, some have got a better clock with a lower uncore.

By the way a lot of the newer batch of i7 4790's seem to have this 4.7 wall, it's *** annoying

 

[Neil79]

Here's a good guide
http://www.overclock.net/t/1411077/haswell-overclocking-guide-with-statistics

 

[hyperseven]

where's your chip from, Malaysia, Vietnam?

Are you using 'Gigabyte tweak launcher' (GTL) to tweak settings from within Windows?

Got a Malay chip form the MM last week, 4.8GHz, 1.25v (pulling 1.262v according to my multimeter full load), 48:42 cache ratio.

only things I have changed:
disabled power states except C3
disabled 'turbo'
CPU VRIN Loadline Calibration: extreme
PWM Phase Control: extreme perf
uncore
multi
XMP1 : profile for memory

think all else is left on auto, the board can sort it out

 

[Neil79]

If it's from OCUK most of the new batches are Vietnam and from what I've seen suck for 4.8 :/

What's your Ring Voltage at bud?

 

[hyperseven]

If it's from OCUK most of the new batches are Vietnam and from what I've seen suck for 4.8 :/

What's your Ring Voltage at bud?

1.22 BIOS (1.237 full load from read points)

 

[Neil79]

Cheers

 

[FL630]

Thanks chaps.

I'm OC'ing directly in the BIOS, wont use the crappy in-Windows OC tools which will just overvolt.

My CPU was made in Vietnam, not purchased from OCUK, so seem to be stuck with 4.7GHz. I can get it to boot no problem at 4.8GHz, but if you stress test it BSOD's at about 4-5 minutes, obviously no good.

Not had a chance to play with voltages as I've been busy with work over the last few days, but I will tomorrow.

I'm following some guides to make sure the CPU volts and clocks down at light load, but still goes up to 1.325v 4.7GHz and remains stable, that's the aim, feels a big one for a newbie to this sort of thing.

Temps at idle on a warm evening in a warm room, 27 degrees with fans at 600rpm, I'm dead chuffed with that.