CPU remains in Idle mode

[Frossed]

Lately I have noticed performance drop when I'm using PC after leaving it for a while in Idle mode. Turns out CPU won't go back to full speed after waking it up from idle, it remains undervolted/underclocked hence performance drop.
One option is to keep it at 100% at all time, but i want that power save mode on.

CPU is overclocked from 3,6Ghz to 4Ghz, keeping voltage options at auto, it was running stable till now (I'm using it for over a year), but I'm not sure if it's fresh matter. It rarely got chance to be idle, but i slightly changed my day routine now, so PC have more idle time now. 

Any help solving this would be much appreciated, thanks.

 

specs:

Intel i5 8600k@4Ghz

ASRock Z370 Extreme4

G.Skill Trident Z 2x8GB DDR4 3200Mhz

MSI GTX 1060 6gb gaming x

Corsair RM650X

Windows 10 Pro

 

I'm using Fractal Define Ctg case with Corsair H100i v2 AIO cooler inside, with 3x120mm corsair SP120L fans mounted on front.

Attached pics are showing CPU voltage and speed before and after idle period.

[unclewebb]

21 hours ago, Frossed said:

Lately I have noticed performance drop when I'm using PC after leaving it for a while in Idle mode.

What is idle mode?  When you resume from Windows Sleep mode, is your CPU stuck at 1400 MHz?  Have you gone to the ASRock website and downloaded and installed the latest bios for your motherboard?  A problem like this might have been fixed in the latest bios.

 

21 hours ago, Frossed said:

but i want that power save mode on

If you want to save power, make sure you have enabled the C States in the bios.  A CPU core in the low power C7 state is sitting at 0 volts and 0 MHz.  This happens automatically when the C states are enabled.  Any other power saving trick cannot compete with 0 volts and 0 MHz.

 

21 hours ago, Frossed said:

CPU is overclocked from 3,6Ghz to 4Ghz

Your CPU is not overclocked.  3.6 GHz is the default speed.  When 1 core is active, Intel Turbo Boost will boost that up to 4.3 GHz.  When 2, 3 or 4 cores are active; the CPU should boost up to 4200 MHz and when 5 or 6 cores are active; a Core i5-8600K will boost up to 4100 MHz.  If you are running your 8600K at 4 GHz, you are running it at less than its default speed.  This is called under clocking and should be avoided.  Go into the bios and set your turbo ratio limits appropriately or set your turbo ratios to AUTO.

 

Go into the Windows Power Options and make sure you are using the Windows High Performance power profile with the Minimum processor state set to 100%.  Also make sure that SpeedStep is enabled in the bios.  On some motherboards, disabling SpeedStep will cause issues like you are having with the CPU getting stuck at a fixed frequency.  

[Frossed]

Thank you for clarifying.

13 hours ago, unclewebb said:

What is idle mode?

I meant leaving PC on for a while while I'm AFK.

C states and SpeedStep were enabled.

As for problem itself, i did updated BIOS today, and kept everything at stock. Problem seems to be gone now, everything works fine. Probably that underclocking was the issue, Thanks for clearing that up. Cheers mate