Question Not Sur If This Is a Bug Or Normal

[Deleted member 2947362]

I'm Just wondering if anyone else can create this and is this a bug with windows or Adia64
or normal?

This happens under Windows 10 or Windows 11

Does this have the same effect with Intel CPU's or is this limited to AMD CPU's?

This doesn't matter if XMP is enabled or not it makes no difference even if I manually set the timings and voltage setting for DDR4 3200

when AMD's SVM is enabled in the Bios and once windows has loaded it puts windows in virtualisation mode.

when I load up Adia64 then run the memory read benchmark my Corsair DDR4 3200 is running at DDR4 3184 not a huge difference but it's not 3200

If I go back to my Bios and disable SVM and benchmark the ram speed again using Aida64 the ram Speed is correct DDR4 3200

If I re-enable SVM back in the Bios and make sure all the memory settings are set to auto with XMP disabled or no manual setup the ram will default to DDR4 2133Mhz which is normal

Ok bare with me.

So, now back in windows SVM is enabled in the Bios, I know everything is set to auto for ram config in the Bios, and ram is defaulted to DDR4 2133Mhz.

Now I'm expecting the ram speed of 2133Mhz to be less by around 16Mhz
So 2117Mhz
Like with the DDR4 3200Mhz was 3184Mhz speeds when under the same O/S environment (SVM enabled)

Still with me?

So I load up Aida64 run the memory read benchmark and ram is running at DDR4 2122Mhz which is 11Mhz less

Again if I disable AMD's SVM in the Bios the Ram will be 2133mhz and the the bus speeds are correct.

CPU-Z also confirms the bus speeds when testing

I know it's a small issue, I agree but never the less why is this happening and does the same anomaly happen with Intel CPU's?
(if it is indeed an issue and not a false reading, but the bus speeds seem to confirm it's not)

Can you create the same result on your PC bug or normal ?

My motherboard seems to love overvolting the ram
With all memory setting set to auto (motherboard defaults) the voltage settings on auto sit around normally 1.24 not 1.2v settings
With XMP profile enabled Voltage should be 1.35v but auto sets voltage to 1.38v

Also just a little rant,

Why is it that these Motherboard manufacturers insisting on overvolting your hardware when you don't want it overvolted beyond it's spec
surly thats not to much to ask?

 

[Deleted member 2947362]

If anyone can help confirm the same happens on their system it would be most appreciated.

 

[Deleted member 2947362]

Lol .. I finally sussed it out.

It was Core Isolation doing it, Why, I have no idea?

All I had to do was disable Core Isolation in Windows security and can leave SVM enabled in the Bios.

Might be handy info for someone, if they are messing around with their systems memory speed settings and seeing lower than rated speed.
Like DDR4 3184 and not DDR4 3200 or whatever the rated speed of the ram should be.

I don't understand why enabling Core Isolation reduces the Bus speed by around 0.5Mhz so its 99.5Mhz rather than it's normal 100.1Mhz, effects the max speed of CPU and CPU Memory Controller.

 

[helper800]

Lol .. I finally sussed it out.

It was Core Isolation doing it, Why, I have no idea?

All I had to do was disable Core Isolation in Windows security and can leave SVM enabled in the Bios.

Might be handy info for someone, if they are messing around with their systems memory speed settings and seeing lower than rated speed.
Like DDR4 3184 and not DDR4 3200 or whatever the rated speed of the ram should be.

I don't understand why enabling Core Isolation reduces the Bus speed by around 0.5Mhz so its 99.5Mhz rather than it's normal 100.1Mhz, effects the max speed of CPU and CPU Memory Controller.

I found an article about it pretty quickly. This is not an unexpected outcome for a security setting. Most security vulnerability fixes decrease the speed of one part or another.

 

[Deleted member 2947362]

I found an article about it pretty quickly. This is not an unexpected outcome for a security setting. Most security vulnerability fixes decrease the speed of one part or another.

I already knew that some types of security mitigations can come at a cost of performance but I have never seen one that effects the FSB speed on my PC.

This is what I would like to know, why is it effecting the FSB speed on my PC?

I had worked out then drop in the FSB was related to SVM somewhere down the line.
Then after messing around in the Bios where the FSB was always showing the correct readings, up until windows had loaded.

I started looking around windows security settings realising Core Isolation is related to SVM being enabled, I'll just try disabling that lol

But why the effect on the FSB once windows has loaded with Core Isolation enabled?

That's the explanation I'm looking for.

 

[Deleted member 2947362]

Also this is why asked if anyone else could test this on their PC's to see if they can replicate the drop in FSB.

I now know it's core Isolation that's causing the drop in FSB on my system.

So does this happen to other peoples PC's when they have core isolation enabled in windows security settings and if so why is this effecting the FSB.

Or is it just my system that's doing it?

 

[helper800]

Also this is why asked if anyone else could test this on their PC's to see if they can replicate the drop in FSB.

I now know it's core Isolation that's causing the drop in FSB on my system.

So does this happen to other peoples PC's when they have core isolation enabled in windows security settings and if so why is this effecting the FSB.

Or is it just my system that's doing it?

I just had a look at CPU-Z and HWiNFO and saw that my bus speed was exactly 100mhz, and 3600mghz effective speed average all day.