Question Anyway to disable the 3D cache temporarily on Ryzen 7 5800X3D?

[Dave3000]

Is there any way to disable the 3D cache temporarily on the Ryzen 7 5800X3D?

 

[A///]

not unless you've got a dual ccd processor, which is only possible with the 7950x3d.

 

[pf100]

I was wondering this myself. Back in the 1990's you could disable cpu cache and I don't understand why they've removed that option nowadays.

 

[adamge]

Is the answer: "Buy a 5800" and swap it in?

 

[gdansk]

There is a control register flag (CR0, bit 30) to disable ALL caches but I don't see one to disable only L3.
I wonder how slow that would be.

 

[StefanR5R]

According to AMD's documentation, server BIOSes can expose an option to the user to switch V-Cache on and off. (I presume that the BIOS maker may decide against exposing this option to users, for whatever reasons.) Therefore I expect that desktop BIOSes may have this option too.

 

[PJVol]

Is there any way to disable the 3D cache temporarily on the Ryzen 7 5800X3D?

Afaik, no.

There is a control register flag (CR0, bit 30) to disable ALL caches but I don't see one to disable only L3.
I wonder how slow that would be.

Where did you see "disable ALL" ?
It says that CR0.CD disables internal caches, not L3 which is considered external IIRC.

https://www.amd.com/content/dam/amd/en/documents/processor-tech-docs/programmer-references/24593.pdf#page=105

 

[Mopetar]

There is a control register flag (CR0, bit 30) to disable ALL caches but I don't see one to disable only L3.
I wonder how slow that would be.

Access time for main memory is about two orders of magnitude slower than cache, so it would definitely be noticeable for most programs.