Enabling EIST/C1E causes BSOD during boot?

[LanceDiamond]

IP35 Pro, Q6600 @ 3.2Ghz (8 x 400 - memory not overclocked) @ 1.325v, 1.27v VTT, 1.33v MCH, 68%/68% GTLCPUREF

What is strange about this is that the system passed over 24 hours of Prime95 at these settings. I noticed I was getting an event in the system event log about power management not being enabled on the processor due to a "firmware problem" and I was curious if that meant EIST/C1E were disabled in BIOS so I enabled them. Result was BSOD loading Windows. I bumped the voltage to 1.355v, same result - bumped to 1.455v (I'd used that voltage during testing and it always worked but produced 10c hotter temps) and booted fine. FWIW, the system event about the processor was related to EIST. I dropped back to 1.325v and BSOD again, disabled EIST/C1E and all is well again.

I searched around and didn't find much about EIST causing bluescreen but I guess it makes sense if I'm at the edge of what my CPU can do at a given voltage - and I am at the edge at 1.325v. At 1.305v I get about 40min Prime95 before a bluescreen vs the 24+ hours at 1.325v.

Thoughts?

 

[Technophobe]

Very similar finding to you. Once I started down the OC path with the halt state and speed stepping settings off and got it very stable with Prime, OCCT. Orthos etc, I thought about being energy efficient and turned them back on. The system became unstable and since I was at the edge of safe volts, I decided not to play with the Vcore anymore and turn those settings back off again (back to stable again).

I'd guess its the variable multiplier causing the CPU instability...

 

[Nenu]

This might help you understand why
http://www.intel.com/support/processors/sb/CS-028855.htm

Its likely that when the CPU load drops, it drops the voltage too low to run the CPU at the overclocked speed.
I dont use EIST for this reason.
The errors may be being reported by/because of Intels power saving software.
Uninstall it if you have it on your system.

 

[chrisf6969]

Its likely that when the CPU load drops, it drops the voltage too low to run the CPU at the overclocked speed.
I dont use EIST for this reason.

QFT.

When the CPU is at less than full load the system is trying to drop down to a slower speed and LOWER VOLTAGE. When it drops the voltage you get your blue screen.

Some processors you can keep EIST it enabled and it still works, some you can't. It just depends.

Both of my processors worked with speedstep enabled.
my e6600 at 9x333 = 3Ghz OC'd and it would drop down to 6x333=2Ghz when idle, but I don't think the voltage dropped.

And now my e8400 works at 9x433 = 3.9Ghz when underload, and when idle it drops down to 2.6Ghz, not sure if the voltage is dropping when speedstep comes on or not. I think the voltage stays the same the whole time.

 

[Mithent]

This may be motherboard dependent, but my Asus board stops dropping the voltage if you have a fixed voltage set, rather than auto voltage?

 

[Forceman]

This may be motherboard dependent, but my Asus board stops dropping the voltage if you have a fixed voltage set, rather than auto voltage?

Yeah, normally manually setting the voltage stops EIST from changing it on idle. I've never seen a board that didn't, but I guess some might.