Core voltage and VID

[tocasa]

Could anybody help me with a voltage question?

I've been overclocking my Sandybridge i5 2500K, increasing the voltage in bios a little. Thanks to OCUK we now have some helpful guidance for sensible voltages to use.

I've been keeping an eye on my core voltage, using CPU-Z. Is this a good choice? - or is there a better program?

I've also been using Core Temp to see how hot things are getting. This shows a "VID" voltage. What is this? It always appears to be different (and higher?) than the core voltage as reported by CPU-Z.

Which voltage does the OCUK advice linked above relate to?

Thanks!

 

[DBT85]

The one that never moves I think is the one the chip is designed to be run at at stock settings. Every chip is rated independantly afaik.

The one that is changing is the ACTUAL voltage being applied, you should see this number go up when under load and down when idle.

 

[tocasa]

In the programs above, both voltages move up and down with load. But they are never the same - I'm not on that PC at the moment, but I think the VID is higher than vCore. It's certainly higher at load - I was running ~1.31V vCore and ~1.36V VID.

 

[Purgatory]

To get the cpu vid , use core temp not cpu-Z that's the current vid the cpu is at when running in cpu-z and it will go up and down as more or less stress is put on the cpu.

http://www.alcpu.com/CoreTemp/

 

[SpoonedurI]

Hi tocasa, VID is the default voltage for your processor and its the number that does not change. Different batches of cpus have different VIDs, in general the lower the VID the better.

The number that keeps changing is the actual voltage that is going through your processor. It will go up under load while remaining low when your pc is left idle. This is the number that the OcUK guide reffers too. Your actual voltage will never go above the safe levels unless you manually overclock it.

Edit: are you sure the vid is changing? I guess that's the effect of TurboBoost. Anyway, vcore is still the number to watch

 

[tocasa]

Thanks folks.

Yes, my VID as reported by core temp is changing with CPU load.
But having looked at the core temp FAQ, I don't think it applies. I will keep an eye on the core voltage as reported by CPU-Z instead.

 

[lollyhayes]

Thanks folks.

Yes, my VID as reported by core temp is changing with CPU load.
But having looked at the core temp FAQ, I don't think it applies. I will keep an eye on the core voltage as reported by CPU-Z instead.

Hey basically the Vid is a number your CPU ships with. It does not change. Are you using a gigabyte motherboard by anychance?
The number that keeps changing may be due to a new voltage regulation spec in sandy bridge called VRD12. and with this the SVID serial Vid which I believe is what you are seeing in cpuz.
Try downloading version 1.56.0 not 1.56.2 and that should have a static number in the box that you currently see changing...

 

[lollyhayes]

oh and core temps Vcore readins are wrong... simply put. It has my vcore as 2.93v... It doesn't appear to have sandy bridge support yet.
If you want a good HW monitor you can get one from the same site as CPU Z its called HW monitor I think...

 

[WingZero30]

Sorry to hijack thread but I would like to ask why VIDs have made a comeback in sandybridge while it was omitted in core i series like i7 920, i5 750 etc? Core 2 like Q6600, E8600 etc had VIDs info aswell.

 

[lollyhayes]

I have a very limited understanding and I'm sure someone will come and enlighten us. But I think that there are common misunderstandings of Vid and what is applicable... My understanding is that there are 2 important points for overclockers:
1. CPU's are not created equal and some will run the same clocks at lower voltages, this is because they have lower Vid's this seems to be the case with sandy bridge and the older gen i7's and i5's.
2. Serial Vid or SVid makes an apperance in SB and allows the CPU to use a preset scalable vid to change operating frequencies... at least this is my understanding of it... it replaces Dynamic vid i think... So when you change your multiplier I think the Vid should look like its changed...

 

[TrojanWhore]

oh and core temps Vcore readins are wrong... simply put. It has my vcore as 2.93v... It doesn't appear to have sandy bridge support yet.
If you want a good HW monitor you can get one from the same site as CPU Z its called HW monitor I think...

also, make sure you're using the latest version, as earlier, on 99.5 mine was reporting 80+ degrees on all cores at idle, and thought my 2500k was an ES