WS 15.0.2 causes much higher kernel latency values in Windows VMs than 12.5.8/12.5.9

I used WS Pro 12.5.x (up to 12.5.8) on Win7 host for two years, running various Windows guests from Win2000 to Win10. For all guests, kernel latencies are acceptable. Of course, latencies are higher in Win10 than in Win7 or earlier, but 12.5.x runs all versions of Windows smooth enough to have glitch-free audio.

Now I tried to upgrade to 15.0.2 and noticed that kernel latencies became much higher in all Windows guests. Under. 12.5.8 or older Workstation versions, I never heard glitches in Win7 audio, and heard glitches in Win10 audio rarely. Under 15.0.2, there are periodical glitches in Win7 audio, and regular glitches in Win10 audio.

WS 12.5.8

Win7 guest, LatencyMon 6.70:

LatencyMon window usually looks "all green" or "mostly green with a little red".

Typical DPCLat window in Win7 guest under 12.5.8:

Win10 guest, LatencyMon:

LatencyMon window usually looks "all green" or "mostly green with a little red".

Typical DPCLat window in Win10 guest under 12.5.8:

WS 15.0.2

Win7 guest, LatencyMon:

LatencyMon window usually looks "distincly red".

Typical DPCLat window in Win7 guest under 15.0.2:

Win10 guest, LatencyMon:

LatencyMon window usually looks "mostly red".

Typical DPCLat window in Win10 guest under 15.0.2:

Disabling USB and network adapters in VMs makes the situation slightly better, but 15.0.2 with USB/network disabled still works much worse than 12.5.8 with USB/network enabled.

All guests are 64-bit, paging is disabled at all.

Host system is MSI GT72S laptop (Intel CM236 chipset, i7-6820HK CPU, 16GB RAM), Win7, paging is disabled, all well-known real-time performance optimizations applied. LatencyMon shows very low latencies in host system. On host system, all audio processing works works quite stable.

All tests were performed in "empty" host system - just booted, with no applications active (even tray-minimized), just usual background services.

Unfortunately, WS 15 appears to be completely unusable for real-time audio processes (I use it for debugging my audio applications and drivers). I had to uninstall it and revert back to 12.5.8.

Why WS 15 introduces so high latencies in the guests? Are there some measures I could take to lower them?