[Solved] Weird CPU/MB problems (8700K + Asus Prime Z370-A)

[Sofronis]

Hi everyone,

I've been having stability issues on High Sierra (10.13.4), with a 8700K + Asus Prime Z370-A.

The main problem (which took a long time to pin down) seems to be with the CPU Voltage. If it's not manually set (through BIOS) at a fixed value, then the system will reboot as soon as, or shortly after, the OS loads. The BIOS CPU voltage modes "auto", "offset" and "adaptive", all have the same behavior. Loading the BIOS optimized defaults, doesn't work either, since that sets the CPU voltage to "auto".

I tried the following, among others, to no avail:

• Install the latest clover version (v2.4k_r4450).
• Create an SSDT for the CPU. It didn't help much, apart from enabling a lower minimum multiplier at idle (10x instead of 13x with "pluginType = true").
• Trying many different SMBIOS profiles.

Also, with RehabMan's latest FakeSMC (along with the sensor kexts), the reported CPU/RAM voltages by HWMonitor, seem to be incorrect, even after having set a fixed voltage (see attached image). Additionally, loading "FakeSMC_LPCSensors.kext" causes one of the case fans to stop spinning.

I have all the recommended BIOS settings, as well as the latest BIOS version (0615), but since I've seen other successful builds with my hardware here, I assume that there must be something that I'm missing.

So yeah, I'm pretty much lost in the woods, on a moonless foggy night here.

Any tips, ideas or suggestions would be greatly appreciated.

PS: Attached you can also find my EFI folder.

 

[deantonibrito]

Hi Man! Did you fixed?
I've got the same problem here

 

[Sofronis]

Hi Man! Did you fixed?
I've got the same problem here

Hi,
yes, I fixed it and it was caused by the power supply.

I initially used my old (from 2010) and not very good PSU (THERMALTAKE TR2 RX 450W), which apparently didn't support Intel's newer C6/C7 low power states. As far as I can tell, if I set the CPU voltage to auto/adaptive/offset and had C6/C7 set to Auto/Enabled in the BIOS, as soon as the CPU had little/no load, it would "fall" into those low power states and the PSU, not designed to work at such low power, would switch off. Setting the voltage manually, essentially disabled those low power states and it worked OK.

The PSU would also often switch off, as soon as I enabled bluetooth (that loaded momentarily both the 3.3v and 12v rails while scanning for devices), but that may be due to it being old and having deteriorated.

Anyway, I got a new high quality Seasonic Focus+ Platinum 850W PSU (it's totally overkill for my current build though) and all those problems went away.

 

[deantonibrito]

Hi,
yes, I fixed it and it was caused by the power supply.

I initially used my old (from 2010) and not very good PSU (THERMALTAKE TR2 RX 450W), which apparently didn't support Intel's newer C6/C7 low power states. As far as I can tell, if I set the CPU voltage to auto/adaptive/offset and had C6/C7 set to Auto/Enabled in the BIOS, as soon as the CPU had little/no load, it would "fall" into those low power states and the PSU, not designed to work at such low power, would switch off. Setting the voltage manually, essentially disabled those low power states and it worked OK.

The PSU would also often switch off, as soon as I enabled bluetooth (that loaded momentarily both the 3.3v and 12v rails while scanning for devices), but that may be due to it being old and having deteriorated.

Anyway, I got a new high quality Seasonic Focus+ Platinum 850W PSU (it's totally overkill for my current build though) and all those problems went away.

Glad to hear that!
Ive changed psu ro corsair ax850 platinum but still have some freezes.
Yesterday, after read your post, ive disabled speed step, multicore asus, and another 2 things in Bios that i dont remember now. All related to auto voltage. And it worked!
Are u overclocked? And whats your temps? Tks man!!

 

[Sofronis]

Glad to hear that!
Ive changed psu ro corsair ax850 platinum but still have some freezes.
Yesterday, after read your post, ive disabled speed step, multicore asus, and another 2 things in Bios that i dont remember now. All related to auto voltage. And it worked!
Are u overclocked? And whats your temps? Tks man!!

I suspect your freezes are related to memory/cpu issues (e.g. overheating) or unstable overclocking. If I were you, I'd run some stress tests (memtest, prime95, video encoding with handbrake) to make sure.

My CPU is delidded and overclocked to 5Ghz (1.375v VCORE under load) and temps hover around 77℃ (ambient ~20℃) after 5-10 continuous runs of Cinebench R15. The CPU cooler is a Thermalright Le Grand Macho RT.

 

[deantonibrito]

I've changed to Imac 18,3 and all ok now.

But wheni plug 2 monitors i lose 15 fps in Cinebench.. is it normal?