I am on Gigabyte H310 S2H 2.0 rev 1.0 with I3-8100 and I am wondering if I can in some way enable SAM since the feature is a part of PCI specs. ASUS Z490 currently support it.

Nvidia is officially launching its own resizable BAR support, which promises increased performance gains in some games if you’ve got the right CPU, motherboard, and graphics card. Resizable BAR has been part of the PCI Express specification for years, but AMD only recently made it an important feature to support with the introduction of Smart Access Memory.

AMD’s Smart Access Memory effectively provides its Ryzen 5000 processors direct access to the GPU memory to bypass I/O bottlenecks. This allows CPUs to access the full graphics frame buffer, instead of being limited to reading 256MB blocks. AMD previously promised up to 10 percent extra performance in certain games — if you pair its new Ryzen 5000 CPUs with its latest Ryzen RX 6000 graphics cards.

But Nvidia says it’s now working with both Intel and AMD, as well as all the major motherboard manufacturers, to bring the feature to “a wide range of motherboards” later this year.
_______________________________________________________
Gordon Bullard & Company