Smart Access Memory not supported by Zen2 but supported by Haswell

[CAT-THE-FIFTH]

It appears AMD has gimped Zen2 in certain ways,so it can't support SAM:
https://www.techpowerup.com/275565/...mitation-intel-chips-since-haswell-support-it

However,Intel CPUs upto Haswell can!! Not at all happy!

This is despite,evidence to show it could work on CPUs and GPUs earlier than Zen3 under Linux:

https://www.phoronix.com/forums/for...e-amd-radeon-rx-6000-series/page4#post1215694

Smart Access Technology works just fine on Linux. It is resizeable BAR support which Linux has supported for years (AMD actually added support for this), but which is relatively new on windows. You just need a platform with enough MMIO space. On older systems this is enabled via sbios options with names like ">4GB MMIO".

I really hope Nvidia can find a way around this,if not Cometlake and CFL users will gain even more performance over Zen2 with newer GPUs!

 

[pc-guy]

It’s a lie. They just don’t want to enable it so that people don’t upgrade to zen3

 

[CAT-THE-FIFTH]

https://twitter.com/IanCutress/status/1337423558042120194?s=20

Got a response from AMD about PDEP and SAM:

'Smart Access Memory does not depend on the performance of the PDEP instruction.'

The speculation about accelerated PDEP on Zen3 being a factor seems to not be the case.