Virtualization Based Security is affecting memory clock


ksio89

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On my laptop (Core i5-1135G7 + 2x8GB DDR4 3200MT/s), when VBS is enabled, I noticed that reference clock (RefClk) shown on HWiNFO64 never reached 100MHz, which in turn makes the effective clock not reach 1600MHz. Every time I turned on the notebook, it read a different value. I was about to create a RMA request believing that my memory was bad, but then I remembered that VBS was enabled and that it reduces the system performance slightly, so I turned it off to test and voilà, the memory now consistently reaches 1600MHz again.

I had enabled VBS in order to use Windows Subsystem for Android, and while I was aware that it had a small performance impact, I didn't imagine that it would also interfere with the memory controller. Has anyone else had this issue? I tested the memory modules with MemTest86 and they passed without any errors, so I guess it's indeed VBS acting up, which is yet another reason to leave it disabled.

VBS on:

MC #0 RefClk=91.0.png
MC #0 RefClk=96.2.png


VBS off:

100MHz.png
 

My Computer

System One

  • OS
    Windows 11 Pro
    Computer type
    PC/Desktop
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    Ryzen 5 2600
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    Gigabyte B450 Aorus M
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    XPG Z1 2x8GB DDR4 3200MHz
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VBS does affect performance yes.

See article here:


Every time I turned on the notebook, it read a different value.

From my understanding, This is because of the virtualization and memory integrity adjusting based on the needs of the performance for the system at the time.

I would still recommended leaving it enabled for security purposes, but that is my opinion.

I don't agree with the Authors assessment that for a home user it does not provide protection enough to warrant having it on.

See this page on how it protects:



Also, I found this:

  • Memory integrity works better with Intel Kabylake and higher processors with Mode-Based Execution Control, and AMD Zen 2 and higher processors with Guest Mode Execute Trap capabilities. Older processors rely on an emulation of these features, called Restricted User Mode, and will have a bigger impact on performance. When nested virtualization is enabled, memory integrity works better when the VM is version >= 9.3.
Your processor is on the Zen+ line, so its older and will be using that emulation so it will be slower with it on.
 
Last edited:

My Computers

System One System Two

  • OS
    Windows 11 Pro
    Computer type
    Laptop
    Manufacturer/Model
    Dell G15 5525
    CPU
    Ryzen 7 6800H
    Memory
    32 GB DDR5 4800mhz
    Graphics Card(s)
    RTX 3050 4GB Vram
    Screen Resolution
    1920 x 1080
    Hard Drives
    2TB Solidigm™ P41 Plus nvme
    Internet Speed
    800mbps down, 20 up
  • Operating System
    Windows 11
    Computer type
    Tablet
    Manufacturer/Model
    Lenovo ideapad flex 14API 2 in 1
    CPU
    Ryzen 5 3500u
    Motherboard
    LENOVO LNVNB161216 (FP5)
    Memory
    12GB DDR4
    Graphics card(s)
    AMD Radeon Vega 8 Graphics
    Hard Drives
    256 GB Samsung ssd nvme
Anything that slows down your reference clock will slow down memory and the entire system. The ref clock is the heartbeat of your PC. If it is not running at full speed, then both your memory and your CPU will slow down according to their multipliers.

If you are finding that VBS is slowing your ref clock, you can adjust it in BIOS to compensate, taking it higher as needed. This may cause some instability if you go too high. I used to overclock my locked CPU this way. I would decrease the multiplier of my memory and then boost the ref clock until I got a stable OC with my CPU. I would try to get the memory back as close to its spec if possible while overclocking the CPU.

It was a kludge, but it worked. These days it isn't necessary because most CPUs are unlocked, but fiddling with your ref clock a little might help offset the performance loss you are experiencing.

I dunno. Just my $0.02
 

My Computer

System One

  • OS
    Win 11 Pro 23H2
    Computer type
    PC/Desktop
    Manufacturer/Model
    Self build
    CPU
    Ryzen 5800X
    Motherboard
    Gigabyte x570 Aorus Elite Wifi
    Memory
    32 GB GSkill Trident Neo with pretty LED lights
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    ASUS TUF GAMING RTX 3070 Ti
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    On board Realtek
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    2 x Samsung 32 inch curved - one 4K, one 1080p
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    1 TB Samsung 980 Pro Nvme, 1 TB Samsung 970 EVO Nvme, 2 x Samsung 970 2TB SSD SATA
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    EVGA 1000Q
    Case
    Rosewill something or other
    Cooling
    Noctua NH-D15. A whole schwak of Noctua case fans. $$$
    Keyboard
    Logitech G815
    Mouse
    Logitech G502 Hero
    Internet Speed
    700 up, 600 down
    Browser
    Firefox
    Antivirus
    MalwareBytes
VBS does affect performance yes.

See article here:




From my understanding, This is because of the virtualization and memory integrity adjusting based on the needs of the performance for the system at the time.

I would still recommended leaving it enabled for security purposes, but that is my opinion.

I don't agree with the Authors assessment that for a home user it does not provide protection enough to warrant having it on.

See this page on how it protects:



Also, I found this:

  • Memory integrity works better with Intel Kabylake and higher processors with Mode-Based Execution Control, and AMD Zen 2 and higher processors with Guest Mode Execute Trap capabilities. Older processors rely on an emulation of these features, called Restricted User Mode, and will have a bigger impact on performance. When nested virtualization is enabled, memory integrity works better when the VM is version >= 9.3.
Your processor is on the Zen+ line, so its older and will be using that emulation so it will be slower with it on.
Memory integritiy (HVCI) was not turned on, only VBS. Also, in original post I mentioned that this was happening on a laptop with an Intel CPU. Anyway, thank you for your reply and for the link, I didn't know the performance impact was that big.

Anything that slows down your reference clock will slow down memory and the entire system. The ref clock is the heartbeat of your PC. If it is not running at full speed, then both your memory and your CPU will slow down according to their multipliers.

If you are finding that VBS is slowing your ref clock, you can adjust it in BIOS to compensate, taking it higher as needed. This may cause some instability if you go too high. I used to overclock my locked CPU this way. I would decrease the multiplier of my memory and then boost the ref clock until I got a stable OC with my CPU. I would try to get the memory back as close to its spec if possible while overclocking the CPU.

It was a kludge, but it worked. These days it isn't necessary because most CPUs are unlocked, but fiddling with your ref clock a little might help offset the performance loss you are experiencing.

I dunno. Just my $0.02
I'm out of luck then, because the BIOS menu of this laptop is very, very barebone, as there are only basic settings like boot priority. And even if the BIOS interface had more features, this is a locked CPU, thus no overclocking. Guess I have no choice but to leave VBS disabled and only enable it when I need to use WSA.
 

My Computer

System One

  • OS
    Windows 11 Pro
    Computer type
    PC/Desktop
    CPU
    Ryzen 5 2600
    Motherboard
    Gigabyte B450 Aorus M
    Memory
    XPG Z1 2x8GB DDR4 3200MHz
    Graphics Card(s)
    MSI Ventus OC RTX 2060 12GB
    Sound Card
    Realtek ALC892
    Monitor(s) Displays
    Acer RG241Y
    Screen Resolution
    1920x1080
    Hard Drives
    XPG Gammix S41 512GB
    Seagate Barracuda ST2000DM008 2TB
    PSU
    Cooler Master MWE 500 Bronze V2
    Case
    Gamemax Fortress TG
    Cooling
    Deepcool Gammaxx 400 V2 Red // 5x Cooler Master Sicklefan red
    Keyboard
    Dell KB522
    Mouse
    Redragon Cobra
    Internet Speed
    300/150 Mbps
    Browser
    Microsoft Edge
    Antivirus
    Windows Defender
Memory integritiy (HVCI) was not turned on, only VBS. Also, in original post I mentioned that this was happening on a laptop with an Intel CPU. Anyway, thank you for your reply and for the link, I didn't know the performance impact was that big.
Sigh, I need to start reading the original posts more slowly. Sorry about that.

And yes, it is pretty decent size, but usually with modern cpu the impact is much lessened.

Glad it helped regardless.
 

My Computers

System One System Two

  • OS
    Windows 11 Pro
    Computer type
    Laptop
    Manufacturer/Model
    Dell G15 5525
    CPU
    Ryzen 7 6800H
    Memory
    32 GB DDR5 4800mhz
    Graphics Card(s)
    RTX 3050 4GB Vram
    Screen Resolution
    1920 x 1080
    Hard Drives
    2TB Solidigm™ P41 Plus nvme
    Internet Speed
    800mbps down, 20 up
  • Operating System
    Windows 11
    Computer type
    Tablet
    Manufacturer/Model
    Lenovo ideapad flex 14API 2 in 1
    CPU
    Ryzen 5 3500u
    Motherboard
    LENOVO LNVNB161216 (FP5)
    Memory
    12GB DDR4
    Graphics card(s)
    AMD Radeon Vega 8 Graphics
    Hard Drives
    256 GB Samsung ssd nvme
Anything that slows down your reference clock will slow down memory and the entire system. The ref clock is the heartbeat of your PC. If it is not running at full speed, then both your memory and your CPU will slow down according to their multipliers.

If you are finding that VBS is slowing your ref clock, you can adjust it in BIOS to compensate, taking it higher as needed.
Why does this look like some secret "eco mode" in disguise? Since when was it VBS=eco-mode?

Also B450=unlocked.

A320 is the locked one, where you can only change RAM settings.

Axxx chipsets are locked down, except for RAM, TMK.

The Bxxx chipsets in Ryzenland are unlocked.
 

My Computers

System One System Two

  • OS
    Windows 11 Pro x64 23H2
    Computer type
    PC/Desktop
    CPU
    Ryzen 9 5900X
    Motherboard
    ASRock B550 PG Velocita (UEFI-BIOS P3.40)
    Memory
    32 GB G.Skill F4-3200C16D-32GVR
    Graphics Card(s)
    Sapphire Nitro+ Radeon RX 6750 XT
    Monitor(s) Displays
    Alienware AW3423DWF OLED ultrawide
    Hard Drives
    Western Digital Black SN850 1 TB NVMe SSD
    PSU
    eVGA Supernova 750 G3
    Case
    Corsair 275R
    Internet Speed
    VTel FTTH 1 Gb down and 1 Gb up
  • Computer type
    PC/Desktop
    CPU
    Ryzen 7 5800X3D
    Motherboard
    Asus ROG Strix B550-F Gaming (UEFI-BIOS version 3607)
    Memory
    16 GB
    Graphics card(s)
    Sparkle Titan Arc A770 16 GB
    Hard Drives
    Samsung 970 Pro 512 GB NVMe SSD
    PSU
    eVGA Supernova 650 GQ
    Case
    Fractal Focus G
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