SOLVED High voltage (Vcore) on SM X10 && Intel Haswell CPU

[DJABE]

Hello community,

I noticed something odd on my X10SLM-F Supermicro and Pentium G3420.
Vcpu Normal 1.764 Volts

That's way too high for a Haswell (at least desktop class) chip!
IPMIView also presents the same readings.

Everything else is fine, VDIMM, 12V, 5V etc. It's just the Vcore this high for some reason.

Interesting, CPU temperature is not an issue, it ranges from 28C to 40C max.
That's odd, since that high voltage would certainly cause CPU to go above 40C at full load...

Is there any way to control Vcore? BIOS doesn't help, there's no option for such.

 

[joeschmuck]

Off the cuff I'd say the voltage being reported back is incorrect. Do you have the latest BIOS version? A screen capture would be nice since I don't have this MB.

And have you searched any forums, mainly dealing with the MB in question?

 

[DJABE]

Hello joeschmuck,
Yes I do have latest BIOS and IPMI (or firmware).

Firmware Revision : 01.35
Firmware Build Time : 03/14/2014
BIOS Version : 2.0
BIOS Build Time : 04/24/2014

I've searched the forums, but not a particular thread pop'd in...

Here's a screen shot from IPMIview (attachment).

 

[Ericloewe]

Haswell has an integrated Voltage Regulator, so the value you're getting may be at the motherboard and not the voltage the CPU actually gets.

 

[DJABE]

Excellent point Ericloewe!
I think this quote explains my situation very well:

One of the biggest additions in Haswell is the full integration of the voltage regulator onto the CPU die. Instead of relying on the motherboard to produce a variety of power rails for different parts of the chip (memory controller, PCIe controller, GPU), Haswell has a fully-integrated voltage regulator (FIVR) that takes a single input (~1.8V) and splits it into all the required rails. The end result is an overall reduction in system power (~20%), comparable idle CPU/GPU power, but a sizable increase in load power consumption (~10%).

http://www.extremetech.com/computin...cpu-in-the-world-unless-youre-a-pc-enthusiast

That's exactly how much voltage a MoBo gives to the CPU!

 

[joeschmuck]

I like that answer!