Core Temp won't show "VID" on i5 520m

I'm on the latest Core Temp version and it's really great... shows me my temperature in the corner just perfectly and I can check what frequency I'm at if I want to.

It doesn't show me my VID though... it's just blank. Any way to fix this? I realize I could probably download cpu-z or another program but I don't want to download another program... that seems like a pretty silly solution.

 

VID will not show for i series CPU in pretty much any program

 

Hm. That's a shame. Thanks for the answer.

 

If your able to read Vcore with some of the other software packages maybe you could request the author of coretemp to include it. IMHO vcore is usually better than VID anyway, as long as it's reading is accurate.

 

If you don't mind... what's the difference? I just was planning on comparing the VID to another computer =p I enjoy seeing how much I've upgraded lol

 

VID is the digitally encoded outputs of the cpu that go the the VRM (voltage regulator). The VRM converts the digital input to an analogue output of the requested cpu voltage from the cpu. The analogue voltage supplied to the cpu is called Vcore. Vcore can be read by hardware such as a super I/O chip and converted from it's analogue value to a digital value to be read by software. The main difference is VID is the requested voltage from the cpu while Vcore is the actual voltage supplied to the cpu. What the processor requests and what it actually gets aren't always the same thing.

 

The requested voltage and the actual voltage for all practical purposes better be the same. The Vcore voltage tolerance for example on i7 quad mobile parts is 8.5mv with PSI# asserted, and 11.5mv with PSI# not asserted. The reason you would see a difference outside of the tolerance from the VID intended voltage would be from measuring errors of the chips you use to convert the analog voltage to digital.

 

Try looking up VDroop.

 

Maybe you should look at the spec.

http://download.intel.com/design/processor/datashts/320765.pdf

Sheets 72, 83-85

The regulators for these guys need to use differential remote sensing. So Vdroop is compensated for by the regulators used for i7 cpu’s by using a feed forward response to actively control the impedance. But even then the impedance from the regulator to the processor should be physically extremely low (especially the inductive impedance) so that large current spikes don’t cause the voltages to swing outside the specification. The specs also state to use properly designed decoupling as needed to keep the voltages within those specs.

 

othonda, did you not manage to find any useful info by googling vdroop or just not bother googling?

This is nothing new. For my C2D P8400 Over Clock I use them for increasing Vcore to help OC'ing the CPU (yet another good reason to measure Vcore over VID).

And it's seems this is what you have based your argument on while leaving out ripple and most importantly the load line.


Here's the load line of the regulator for my P8400. Note how VID is set to 1.150V but @ 40A Vcore will be somewhere around 1.060V.



And here is one for socket 1156 presented as a deviation from VID. Note that even though the tolerance band is ±19mV when current increases to ~60A then Vcore will likely be ~100mV less than what VID is requesting. ie if VID were 1.3V then @ 60A Vcore would be ~1.2V.



Look at the graphs in the document you quoted. Vcc nom (Vcore) is not a straight line wrt Icc (core current) but slopes down. In other words Vcore reduces as current increases, a typical load line design characteristic that you have chosen to ignore.