Undervolting Haswell - your experiences

[Nec_V20]

I got my new board GigaByte GA-Z97X-Gaming G1 WIFI-BK for use with my older 4770K (I had the GigaByte GA-Z87X-UD5H before) and decided where I could go with undervolting.

I have set it up in the BIOS so that the CPU is at stock and Turbo is enabled to 3.9 for all cores.

The way I undervolt is by setting the CPU VRIN to "Normal" and then using the CPU VRIN Offset option.

I started off at -0.075 Volts and did benchmarking with OCCT, playing games (Diablo III Reaper of Souls, Starcraft II, X3 Albion Prelude) and just generally using the computer and of course leaving it powered on 24/7 for a few days.

That proved to be stable so I went to -0.090 V and did the same thing as above.

I then went to -0.1 V and again did the testing.

I have now had it running at -0.125 V since yesterday and it is still running through all the tests and games without a hitch. Running OCCT 4.4.1 CPU-Z tells me that the CPU is running at 1.087 Volts.

Have any of you undervolted? And if so what is the lowest you have managed to run stably.

It would also interest me if any of you have undervolted the 4790K and how far you managed to push that.

 

[sm625]

Do you have a kill-a-watt?

 

[Nec_V20]

Do you have a kill-a-watt?

I have something similar, but I loaned it to my friend who wanted to see how much electricity he was drawing and of course he has not given it back yet although I have been asking him for it for months now.

I am interested in how much people have managed to undervolt their 4770K/4790K or other CPUs and still have the system running stably.

I am not so much interested in how much energy it actually saves (though I will be measuring that sometime in the future when I get my Watt meter back).

 

[Edrick]

I know its not the K model, but I have a 4770 at max speed (3.7-3.9) at 1.024v. Running very cool on a low end air cooler.

 

[Nec_V20]

I know its not the K model, but I have a 4770 at max speed (3.7-3.9) at 1.024v. Running very cool on a low end air cooler.

Did you undervolt it so that it was running a benchmark like OCCT at that voltage or is that just normal running?

When I am just copying files via the WiFi on my system the voltage is between 0.58 V and 0.61 V and it gusts barely quick enough to see to 1.084 V occasionally.

I would be very happy if I could get my 4770K down to anywhere near 1.024 V running OCCT. That would be an undervolt offset of -0.185 V.

 

[Edrick]

Did you undervolt it so that it was running a benchmark like OCCT at that voltage or is that just normal running?

When I am just copying files via the WiFi on my system the voltage is between 0.58 V and 0.61 V and it gusts barely quick enough to see to 1.084 V occasionally.

I would be very happy if I could get my 4770K down to anywhere near 1.024 V running OCCT. That would be an undervolt offset of -0.185 V.

I set my voltage directly in the BIOS and turn off EIST so the voltage runs at a constant 1.024v. Prime95 (FMA) and LinX stable. Temps never hit 70C using a low profile Zalman cooler (air).

I don't use the offset method. I find I can undervolt easier without it.

Edit: I also turn off LLC in the BIOS.

 

[LTC8K6]

I think I ran my 4790K at 1.035V

It was stable with all 4 cores at 4.4, and much cooler.

Let to itself, the BIOS applied some crazy high voltages.

I should be firing it up again tonight to install WIN10, and I will confirm the setting.

 

[PPB]

Mine has a vid of 1.002v for 4.0 clock, my aim is to clock it the highest 1.0v would allow.

 

[LTC8K6]

Yes, I found my notes. 1.030 was unstable at 4.4, 1.035 was stable.

 

[richierich1212]

Looks like my 4790K + Z97i-Plus is only able to undervolt to 1.067v under load @ stock turbo settings. Any lower and my computer freezes in the BIOS. I'll leave it as is. Oh, and it idles at 0.614v. That's pretty sweet for a Quad-Core with 8 threads.

 

[Magic Carpet]

Haswell (4770K) was the first CPU, I didn't find undevolting that useful. There were some gains temp/power wise but much less than I anticipated. If you want to save power, underclocking would be a must as well.

 

[CakeMonster]

I had to undervolt my old HW, or else it would run amok with voltage at anything above stock speed. Current mobos throw crazy voltage at CPUs, and its often difficult how to make them stick to the voltage the CPU is supposed to run at.