Intro

During my testing of the 9900K I noticed an oddity. It was pure chance that I ran into this bug. I was messing around with Windows Subsystem for Linux which I already had enabled on my Windows 10 install. I got fed up with it for one reason or another which isn’t relevant and removed it. The next day when I continued with my frequency stepping tests, I saw lower clock speeds (with WSL2 related features disabled) beating higher clock speeds (that had WSL2 related features enabled) in AIDA64 and other tests I was running.

Setup

Test System

For my test system I’m using the same hardware as in my 9900K review:

  • Hardware Provided by Intel
    • Intel Core i9-9900K
    • Noctua NH-D15
    • ASRock Z390 Taichi
    • G.Skill Trident Z RGB F4-3466C16D-16GTZR
    • Samsung 970 EVO Plus 250GB NVMe
    • Fractal Design Define S2
    • Seasonic 850w Focus Gold
  • My Personal Hardware
    • EVGA RTX 2080Ti XC Black
    • PNY CS1311 960GB SSD
    • SanDisk Ultra II 480GB SSD

Software

For the quick tests as of now I’m using AIDA64 Extreme Edition version 6.00.5100 along with Windows 10 Pro Insider Fast Ring 18963.rs_prerelease.190814-0221. When WSL2 is enabled nothing is actually installed for it, as in, I don’t have a Linux distro set up or running or anything. The only thing that changed was these Windows 10 features being enabled or not. All testing is done with no internet access and I also wait for a completely idle CPU usage.

How to replicate the bug

Usually your installed Windows 10 features would look something like this:

The first thing you need to do is either enable Windows Subsystem for Linux or run this command in an administrator PowerShell:

Enable-WindowsOptionalFeature -Online -FeatureName Microsoft-Windows-Subsystem-Linux

Then reboot.

The next thing you do is enable Virtual Machine Platform or run this command in an administrator PowerShell:

Enable-WindowsOptionalFeature -Online -FeatureName VirtualMachinePlatform

Then reboot.

The Results

Asus RealBench 2.43

wsl2bugrealbenchplot

Cinebench R15 & R20

wsl2bugcinebenchplot

AIDA64 Extreme Edition 6.00.5100

AIDA64 CPU Tests

wsl2bugaida64cpuplot

AIDA64 Memory Tests

wsl2bugaida64memoryplot

GeekBench 4.3.4

GeekBench 4.3.4 Single Core

GeekBench 4.3.4 Single Core CPU
wsl2buggeekbenchsinglecoreplot
GeekBench 4.3.4 Single Core Memory
wsl2buggeekbenchsinglecorememoryplot

GeekBench 4.3.4 Multi Core

GeekBench 4.3.4 Multi Core CPU
wsl2buggeekbenchmulticoreplot
GeekBench 4.3.4 Multi Core Memory
wsl2buggeekbenchmulticorememoryplot

Passmark PerformanceTest 9.0 Build 1031

Passmark PerformanceTest CPU Tests

wsl2bugpassmarkcpuplot

Passmark PerformanceTest Memory Tests

wsl2bugpassmarkmemoryplot