Skylake hard locks seeminly when IDLE / CStates ON

[GGlyn]

Myself and others have been struggling with a different hard lock problem with Skylake and we have ran out of options but to assume it is a CPU fault/issue. Does anyone have any comments or feedback?

The long thread is over here, but I will summarise. http://www.tomshardware.co.uk/forum/id-2830772/skylake-build-randomly-freezing-crashing/page-7.html New Skylake Build Randomly Freezing/Crashing - Page 7 - windows 10 - Windows 10

Our systems hard lock randomly but appears on the most part to be when IDLE or next to IDLE. The hardlock can come when playing video, browsing (reading) or mostly when not interacting at all. Some (like myself) noted that they seem to occur more often if you are doing a large amount of disk IO (partition move for example or copying 40+ GB of data disk to disk).

Hard locks happen in either Windows (7,8,10) or Linux.

With CStates on, the crashes are often and usually within 10 minutes of IDLE. With CStates disabled completely most find that the system remains "mainly" stable for days. Generally, no one has reported locks when gaming or under high CPU load (so I do not think this is the Prime95 example but then, since compilers / drivers use the latest instructions (according to CPUID) I cant be sure).

The symptoms happen on many different manufacturers motherboards, RAM types and setups. We have successfully removed or replaced all components and the only change that seems to make a difference is CPU for a few. CStates off in the BIOS is absolutely a guarenteed way to stabilize significantly but not fix.

I changed CPU (after trying everything else) and find it now mostly stable with CStates ON. I must be clear that my system is 100% identical, CPU # 1 crashes all the time and must have CStates off, CPU # 2 does not crash so often even with CStates ON. One may argue this is a problem with my PC, a fault, but with so many people having the exact same issues I cant believe it is a defect. And with Cstates/SpeedStep so specifically (a known new part of Skylakes architecture), I remain convinced that this is something real.

Others were not so lucky, a replacement CPU did not make the situation better. Batches from different factories as well etc etc

My new CPU has hard locked but not when IDLE like the last one (not yet anyway). Mine can lock when under full load, video transcoding, but not more than 1 in 10 sessions. Cstates ON seems equally stable on this CPU as OFF.

Thanks for any suggestions you can give.

[CCris2]

Most times those freezing problems are not from CSATES or vcore. They are from memory incompatibility, or because unexperienced users start to overclock without knowing what are they doing.

I noticed that on asus, although memory is in QVL listing, the mainboard does not set the right voltages on XMP, for CPU memory controller, memory and VCCSA.

EVGA seems to have less problems with their mainboards, but I don't think they sell to many, maybe because they have higher prices. But that's just an observation.

[ssote]

Pentium G4400 GA-H110M-A, G.SKILL NT Series 8GB (2 x 4GB) 288-Pin DDR4 SDRAM DDR4 2133. The PC has not froze in 30 days with C states off and Vcore at +0.050v I don't what to run it that way.

I did a memory test, memtest86 it passed, ran prime95 24 hours it passed, the PC just does not like to idle sometimes that is what this post is about. Intel said it is a defective CPU.

[CCris2]

Do you have a discrete video card or you use the igpu ?

[ssote]

IGPU

[CCris2]

If you have a separate video card,it is worse if it's old, then I advise you to remove it and try to see if you have any problems when you run just with the igpu at default voltages with c-states on.

If you do not have any discrete card, and your memory runs at normal timings 15 15 15 36 2 - 2100 , and you have problems with mainboard on default settings, then it is a hwardware problem, with CPU or mainboard.

These all should be done with the latest bios available for your mainboard, although I saw that the bios is a little old (your mainboard is a cheap mainboard and it gets the updates a bit later then the expensive ones).

[CCris2]

Those memory timings I guess are correct, but you should let memory on auto or XMP.

[ssote]

Ronin wrote:

If you have a separate video card,it is worse if it's old, then I advise you to remove it and try to see if you have any problems when you run just with the igpu at default voltages with c-states on.

If you do not have any discrete card, and your memory runs at normal timings 15 15 15 36 2 - 2100 , and you have problems with mainboard on default settings, then it is a hwardware problem, with CPU or mainboard.

These all should be done with the latest bios available for your mainboard, although I saw that the bios is a little old (your mainboard is a cheap mainboard and it gets the updates a bit later then the expensive ones).

It is a IGPU I don't have a dedicated video card. The G.SKILL NT Series 8GB (2 x 4GB) 288-Pin DDR4 SDRAM DDR4 2133 is stock intel specified memory it is set on Auto. The memory does not have intels XMP (Extreme memory profile), XMP is for people and board manufactures memory company's that want to setup the memory, timings, and voltage overclock the memory past intel's stock specifications.

About the Bios, the budget boards sell like hotcakes with all manufactures they get the most attention with Bios and problems first. I checked Newegg and my board out off all the Gigabyte boards for 1151 is the 1 best selling. Sort by Best selling

http://www.newegg.com/Product/ProductList.aspx?Submit=ENE&IsNodeId=1&N=100007627 http://www.newegg.com/Product/ProductList.aspx?Submit=ENE&IsNodeId=1&N=100007627 50001314 600567584

I will check my stock core voltages later today.

[CCris2]

From what I saw with bioses is the other way around. They make tests on high end board bioses and after that they modify the low end after 1 month +... GA-H110M-A last bios is F5, dated 2016/03/22 , and GA-Z170X-Gaming G1 last bios is F8k dated 2016/06/20. And it's not the only one manufacturer on which i noticed that.

[PMan]

The investigation continues !

As advised by Ronin, i bought new memory recomended for my NUC Kit "NUC6I5SYH".

This new memory is Samsung - 8Gb DDR4 2133 (PC4-1700, CL15)

BUT inopportune stops always arrive

I end up losing my cool.

I think I'll ask my replacement NUC.

If you have other solution, do not hesitate.

Thank you all for your help

[CCris2]

Reset bios, and if you still have problems then go for replacement.

[PMan]

Thank you very much for all that information.

Does anyone know how to set different voltages on my NUC Kit "NUC6I5SYH".

I have not found where it is in the bios

Thank you all for your help

[CCris2]

It should be written in manual.

But I am afraid that on that NUK you don't have voltages ...

Maybe look at Power tab.

[PMan]

Ronin, thank you for your rapid response

I'm afraid you're right for mu NUC, here is the Power Settings available :

It seems to be "Light"

[CCris2]

Can you give me a screenshot with memory settings ?

[CCris2]

I think you need Command rate 2n. If you set it on 1n you need to increase memory voltage and other voltages and is not possible ...

[PMan]

Thank You Ronin,

The Memory Settings are :

Do you think that setting Command Rate to 2n will solve my NUC Freeze problems ?

[CCris2]

You should do a full bios reset on that NUC, and don't do any manual modifications. If you don't know what to modify, any modification you make can lead to instability, errors and freezing.

Memory can support the modifications you make, but the CPU needs voltage modifications, and that can not be done on this model.

And Command Rate should be 2n, because it doesn't have necessary voltage control.

[PMan]

Hi Ronin,

Aas advised, i've set command rate to 2n BUT UNFORTUNATELY inopportune stops are still there

I therefore conclude that the CPU is defective, I will ask my replacement NUC.

I keep you informed.

Thank you for all your help.

[CCris2]

Hi @PlexMan ,

Sorry to hear that. Good luck on the next to be a good one.

[LMonk]

Hello! Currently i run my skylake 6600 without any freq scaling and c-states. Ten days uptime. How do you think if i got stability in such way, what i must to do next?

[CCris2]

Hi lks70 ,

What is the bios version you have at the moment ?