Intel i5 6600K random lockup Freeze or BSOD...

[satas]

Hi to all!

firstly here is my configuration:

Intel i5 6600k at stock speeds

Asus Z170 ROG VIII Gene (latest bios 1504)

Corsair DDR4 16GB (2x8GB) 2400MHz (CMK16GX4M2A2400C14)

EVGA GTX980 SC (at stock speed)

I am experiencing random system freezes and BSODs. The screen locks up and the sound is stuck or it is just BSOD.

I already started a thread over at Tenforums and did a lot of troubleshooting but nothing really helped.

most of the time the issue happens while just browsing the internet, playing some flashgame in the browser etc.

it can randomly happen with listening to music with wmp or aimp or just while starting a portable application from usb drive.

it's really very random and unpredictable, that makes it very difficult to analyze - but the issue is there in the background all the time.

I'm running Windows 10 Pro and have the all the latest bios and drivers installed.

there is no manual overclock except the ram running on XMP profile at 2400MHz (instead of 2133Mhz).

how is it possible that Intel's Skylake can not handle ram at 2400MHz while Z170 chipset advertises speeds at >3000MHz.

Thank you in advance for the help and advices,

Sahin

[CCris2]

All I can see on my mainboard is that CPU PLL starts from 0.900. I don't even have lower options.

[CCris2]

And I looked on Asrock forums no one was complaining about cpu instability ... and I mean not even one post about that.

[satas]

Ronin wrote:

And I looked on Asrock forums no one was complaining about cpu instability ... and I mean not even one post about that.

it depends on where you're looking at, every overclocker knows what it is. but is is not really common at stock speeds indeed.

additionally it's not very easy to identify the cpu as a cause for casual user, you just see a crash, BSOD or whatever.

to identify the cause needs more knowledge, experience even additional spare parts.

Ronin wrote:

All I can see on my mainboard is that CPU PLL starts from 0.900. I don't even have lower options.

evet that you should see only in manual mode and not on "auto" setting. with set on auto you should just see the current reading and that's it.

[CCris2]

I am telling you this not from overclocking point of view. I am telling you because I believe your mainboard has a problem with the circuit for that voltage, and that guy that has same configuration as you is just lucky that his CPU works at that PLL voltage.

In description in bios the normal value is 0.9 on auto. It is clearly written that normal value is 0.9, and it should be increased only in case of overclocking to maintain system stability and should not be higher then CPU Core voltage.

What I told you is to increase it slightly from 0.6 to 0.610, 0.620 and so on till you find the right value for the CPU to be stable at idle.

This is what i found on this webpage http://www.hardwareluxx.de/index.php/artikel/hardware/prozessoren/36917-skylake-richtig-einstellen-was-man-machen-sollte-was-man-lassen-sollte.html?start=3 Skylake richtig einstellen: Was man machen sollte, was man lassen sollte - Hardwareluxx

It is and undervolt for Core i5-6500T on an Asus mainboard.

Undervolting: Core i5-6500T + ASUS Z170 DeluxeCPU Core Voltage Offset-0,15 VCPU VCCIO Voltage0,85 VCPU System Agent Voltage0,95 VPLL Termination Voltage0,85 VPCH Core Voltage0,9 VCPU Standby Voltage0,9 VDRAM VTT Voltage0,5 VVPPDDR Voltage2,1 VDMI Voltage0,8 VCore PLL Voltage0,85 V

As you see on a lower frequency CPU then yours they set CPU PLL lower then 0.9, but is not 0.6 ...

I don't know why your mainboard is setting that voltage to 0.6 ...

[satas]

well those guys were trying to lower voltages just to see how much more energy efficient the system can be.

they measure how much they can lower the energy used by the system especially at idle.

with that said here I'm including 2 schreenshots forum Asus Z170 Deluxe and Asus Z170 Gene respectively.

I just had a look at the both manuals and saw the very same ranges for the Core PLL Boot Voltage.

the ranges for the Core PLL Voltages are a bit different with the Deluxe having a wider range.

basically the Deluxe has Core PLL Voltage and Core PLL Boot Voltage ranging form 0.7V to 2.4V for both (manual mode).

the Gene has Core PLL Boot Voltage ranging from 0.7V to 2.4V but a Core PLL Voltage ranging from 0.7v to 1.6V (manual mode).

while I don't know why those guys set Core PLL Voltage manually to 0.85V I see that in manual mode it starts from 0.7V.

that's not that much away from 0.6V which obviously seems to be just set automatically by the motherboard.

the guys from the review don't mention the Core PLL Voltage auto reading so it could be 0.6V as well.

I don't know why you do assume it has to be 0.9V at least, there are so many factors which could affect this value at auto mode.

not to forget that the memory management issue should be related to IMC on the cpu, if at all.

Core PLL Boot Voltage ranges:

Core PLL Voltage ranges:

update: by the way I'm running crash free for about 48 hours now, crossing fingers.

[CCris2]

That memory errors u might get from CPU cache also ... That why is important CPU PLL Voltage..

Intel CPU has 2 states idle and when under load.

When idle multiplier is x8 and under load multiplier is higher then x8

When idle CPU power comes from CPU PLL. If the voltage is not enough u get errors or freeze. CPU PLL is stabilizing the Voltage when CPU goes from idle to load mode also.

When under load the cpu power comes from Vcore voltage.

And another thing.

Skylake frequency when in idle mode should have been 8x100Mhz(Bclk when idle) = 800Mhz (System Agent Frequency). After release they changed it to 8x125Mhz=1000Mhz(System Agent Frequency), and I think on Asus that is default. That means that it needs higher voltage for CPU PLL OC voltage because Bclk was increased with 25Mhz ...

[satas]

I understand your point but somehow it doesn't match what I see on my readings.

at idle I have 8x multiplier and arond 100MHz bclk, actually between 99,95MHz and 100.05MHz.

but never 125MHz, as there were quite some bios versions after release maybe they adjusted that.

additionally I can't get the point why should a system run for couple of days on PLL 0.6V and then crash on the very next day.

but I do understand that the value is somehow irritating, maybe because we just don't know what's going on in the voltage algorithm levels on auto settings.

[CCris2]

Did you modified the core voltage ? Because is a bit to high. Look at my voltage on auto.

And here are my voltages on auto:

[satas]

no, I haven't modified the cpu core voltage but I loaded optimized defaults in bios.

it could be that some energy saving settings are not enabled by default, I didn't have a look at it yet.

[CCris2]

You have a problem with mainboard for sure. Do a bios reset and check the voltage, because is very strange. On my mainboard I don't have full control of PLL circuit, I can control only the Voltage that powers it ... On Asus mainboards I saw that there is more control in bios., like:

CPU PLL OC

CPU PLL SFR

CPU ST PLL

As you see in HWiNFO it doesn't even show it there.

[CCris2]

And in an earlier post you said that VTT = VCCIO is not ... I have VTT also and VCCIO and they have different voltages ... On skylake I think VCCIO is the signal amplitude between memory controller and memory. And I think VTT is other signal amplitude, maybe is for DMI, I am not sure. On skylake is a bit different.

[satas]

there could be differences with respect to that matter between the manufacturers.

I also see that you have different sensor model although the same brand.

we spakulated VTT could be VCCIO for the Asus Z170 Gene model, not for all.

lots of the readings are differently named in HWInfo for different mainboards.

by the way what ram model are you using and is it on XMP setting?

[CCris2]

Is Corsair CMK16GX4M2B3200C16R 2x8GB 3200, and yes is on XMP.

[satas]

then it must be motherboard related difference as the other guy on the ROG forums using the same combo has the same readings as me.

[CCris2]

You can check what is what by putting voltages manually

[CCris2]

The memory voltage setting must be same for any mainboard with the same memory because the memory controller is in the CPU, and the voltages needed must me the same for the memory controller and memory to run correctly.

But what if your mainboard has a problem with reading voltages or setting them right ... Or what if the manufacturer didn't respected all Intel CPU specifications, and set the voltages lower then specifications for those CPU's they received for testing to work. And that guy received a CPU that is working with the voltages Asus used for the testing CPU's, and you got a CPU even 2 CPUs that didn't matched those values.

Thats why I am telling you that there is something wrong there.

[satas]

you still mean the Core PLL Voltage I assume? what is your reading for it under auto settings?

obviously you don't see it in HWInfo so you can see it in the bios I assume.

by the way the higher cpu core voltage on my side was just a bios setting.

leaving the core voltage on auto keeps it around 1.2V but choosing "Adaptive Voltage" I have the same reading as you.

although I can't explain the PLL voltage difference I have a sneaking suspicion what may have caused my troubles all the time.

I'm not really sure so I'll wait a bit longer, I'm on XMP settings for almost 72 hours with no crash now.

I have a good feeling about it after all...

[CCris2]

Well what is your suspicion ?

I can't read in any way PLL voltage on my mainboard, but I tested and when I change it it increases slightly idle CPU voltage.

[satas]

I suspect the Asus cpu installation tool and an exceptionally slightly bent motherboard pin, probably by default.

[CCris2]

Well it maybe, I saw your mainboard socket in those pictures, and is different then mine . The socket of my mainboard is build in that way so even if pins are bent they will still make contact (in the plastic beneath them in the direction they are bent is build a little socket of the size of the pin, and the pin is behaving like a little sping like here if you can see: https://www.google.ro/imgres?imgurl=http://proclockers.com/sites/default/files/ASRock_Z170_Gaming_K6Plus_12.jpg&imgrefurl=http://proclockers.com/reviews/motherboards/asrock-z170-gaming-k6-motherboard-review/page/0/2&docid=ag78rtus_1WzWM&tbnid=1Wk9HptIPGROWM:&w=1000&h=750&bih=939&biw=1680&ved=0ahUKEwjm7pbtmJbMAhUQKywKHWMfBUgQMwhxKEwwTA&iact=mrc&uact... https://www.google.ro/imgres?imgurl=http://proclockers.com/sites/default/files/ASRock_Z170_Gaming_K6Plus_1…).

[satas]

As far as I know all sockets are the same, no matter which z170 motherboard you use.