Virtualization Based Security is affecting memory clock

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:





VBS off:

VBS does affect performance yes.

See article here:

ksio89 said:

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

Click to expand...

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.

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

andrew129260 said:

VBS does affect performance yes.

See article here:

Tested: Default Windows VBS Setting Slows Games Up to 10%, Even on RTX 4090

Virtualization Based Security (VBS) has a big impact on frame rates.

www.tomshardware.com

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:

Virtualization-based Security (VBS)

Provides guidance on what an OEM should do to enable VBS

learn.microsoft.com

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.

Click to expand...

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.

Catnip said:

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

Click to expand...

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.

ksio89 said:

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.

Click to expand...

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.

Catnip said:

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.

Click to expand...

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.