My G3258 Vcore doesn't drop when idling.

[jana519]

New to overclocking. I just picked up a G3258 and Asrock H81M-ITX. I updated the BIOS to 2.1. I have the ratio multiplier set to 41 and everything else is perfectly stock settings.

My problem is when I open CPU-Z or HWInfo, it shows the Vcore at 1.2 for 4.1Ghz. Now when the CPU idles at 800 MHz, the Vcore doesn't drop. It remains at 1.2. Is this normal or is the Vcore also supposed to go down?

Edit: EIST is enabled

 

[know of fence]

Set Vcore mode to [Adaptive] instead of (Override).
Also you can try setting turbo mode to [Enabled], even though Pentium CPUs don't have Turbo states, disabling it in the BIOS did mess with the OC.

You can (provided the bios allows it) set a manual Vcore and a negative offset to further reduce power consumption.

 

[jana519]

OK, went back into BIOS after taking your advice. I can enable manual Vcore and a negative manual offset, but it doesn't give me an Adaptive offset option. I see Adaptive offset listed on the sidebar when I highlight the Vcore voltage settings, but it's not in the dropdown menu.

This is a quirky motherboard. It came to me with BIOS 1.6, which let me overclock in BIOS options but it didn't stick when loading Windows. I updated to 2.1 and now the overclock sticks, but I think I lost Adaptive offset. I believe it was available in 1.6. Hmmm, this is tricky.

 

[know of fence]

In the ASRock Z97 BIOS the option is called:

"CPU Vcore Voltage Mode" --- [Adaptive/Override]
Also there is a similar option for the Ring/Cache/Uncore part of the CPU.

Never mind offset for now. But looking at your board manual the H81 boards are quite different, they should still have that option. Try to disable "Vcore override Voltage" (page 52).

 

[jana519]

Yep, Vcore override voltage is the same as Manual. When I disable that the only option I can select is "Auto".

I could try to roll back the BIOS to 1.9, that might make Adaptive available. But I'm not sure why Asrock would disable it in the newer version?

Actually I've been doing some reading on Adaptive voltage and some people claim manual is better. Is Adaptive offset going to give me a significant benefit or can I ignore it?

 

[know of fence]

Manual means setting something by hand, override means that the set value won't be changed. They should not be the same. For instance, I type in the (highest) Voltage manually in Adaptive Vcore mode. The highest Voltage is fixed but for lower clocks the CPU picks appropriate voltages from an internal VID table.

It is possible that only Override overclocking is enabled with this board. Override OC is better in the sense that it's a simple and more stable because there are less unknowns.

With default settings and 32 multi, the CPU will probably scale both voltage and frequency. So you should at least try that to actually see how voltage scales, in CPU-Z.

Also, HWinfo64 shows CPU Package power very precisely, so you can compare those numbers with and without the overclock and/or voltage scaling. Because this is a dual core CPU the whole difference of DC power consumption should amount to about 35 W, (up to 1.221 V overclocks) roughly half of it you save by scaling voltage, the other half by scaling frequency. So that's 15-20 W at the wall in low power states.

 

[jana519]

Manual means setting something by hand, override means that the set value won't be changed. They should not be the same. For instance, I type in the (highest) Voltage manually in Adaptive Vcore mode. The highest Voltage is fixed but for lower clocks the CPU picks appropriate voltages from an internal VID table.

It is possible that only Override overclocking is enabled with this board. Override OC is better in the sense that it's a simple and more stable because there are less unknowns.

With default settings and 32 multi, the CPU will probably scale both voltage and frequency. So you should at least try that to actually see how voltage scales, in CPU-Z.

Also, HWinfo64 shows CPU Package power very precisely, so you can compare those numbers with and without the overclock and/or voltage scaling. Because this is a dual core CPU the whole difference of DC power consumption should amount to about 35 W, (up to 1.221 V overclocks) roughly half of it you save by scaling voltage, the other half by scaling frequency. So that's 15-20 W at the wall in low power states.

Great info thanks. Yeah I think because it's a B85 board and Pentium G3258 I can't enable the Adaptive Offset settings. But I guess since it's just 2 cores, the extra watts won't make a huge difference overall.