Stutters - CPU spikes

Hello!

After about 30 minutes of Path of Exile 1 gameplay, game becomes incredibly laggy with CPU graph spiking up to ~200ms and stopping frames from generating for same period. After 5 minutes of lags game goes back to running normally, then loops over to stuttering again, and so on.

Graph looks like this:

Game was running fine in first 20% of graph. CPU graph (red) shows values around 200 ms on first frame after lagspike and then rapidly decreases to normal value.

During spikes all my inputs are completely discarded as if I never pressed any buttons - character moves in same direction as before lag started (also Cyclone keeps being channelled in same direction), skills and flasks don't get activated, items don't get picked up or stashed or put in vendor's window.

From what I already know it can start happenning in both maps and hideout.

I started noticing these lags after I switched to Vulkan renderer.

I found no one else posting about this exact problem here at Technical Support forum, as they never mentioned such periods of lagspikes and running normally.

Among things I tried to fix lags were:

- Solutions posted in General Troubleshooting Guide;
- Turning off CPU C-States (also tried changing minimum and maximum processor state for power management);
- Disabling HPET drivers;
- Disabling CPU cores (up to 6 cores from 12 available for my PC);
- Setting priority for PathOfExile.exe to High;
- Updating GPU drivers;
- Reinstalling Windows.

Is there anything else I can try to fix stutters?

Thanks in advance!