SAM working with older AMD Graphics Cards and Zen+ Processors?

[Yagai]

Hello,

recently I discovered that a new BIOS Update was available for my MSI B450 Pro-VDH-MAX, which introduces Resizeable BAR Support. So, out of curiosity, will my Ryzen 5 1600 AF and my RX 570 get any performance boost with it enabled? I mean, all it does is enabling the CPU to use all of the GPUs VRAM, right?

 

 

 

[Stahlmann]

Currently it's locked to Ryzen 5000 CPUs and RX6000 GPUs only and needs PCIe 4.0.

[GamerDude]

Nope, I've heard certain mobo makers, like MSI, have been releasing beta BIOS to enable SAM. PCIe 4.0 isn't necessary to have SAM enabled. I've read that even RX 5000 series owners have had SAM enabled on their mobos too (using a Ryzen 2700X for example). Now whether PCIe 3.0 has enough bandwidth to support SAM fully, or that RX 5000 series cards can take advantage of SAM is.....debatable at best.

 

To refute Stahlmann's claim, my X570 mobo (latest beta BIOS that support SAM, Adrenalin driver must be 20.11.2 or later I think) + R9 3900X + RX 6900 XT has SAM enabled, proof's in the pudding. The screenshot below was taken when I had an RX 6800, which was since replaced by the 6900 XT. The 'Large Memory Range' is an indicator that SAM has been enabled.

 

I've heard that there may be more BIOS releases from the various makers, to extend SAM support to earlier AM4 platforms like X/B 300/400 series mobos. The answer as to whether this can and will be done is a question of time.

 

[porina]

1 hour ago, Yagai said:

will my Ryzen 5 1600 AF and my RX 570 get any performance boost with it enabled?

Try it on and off for yourself, for the games you care about. Otherwise you can try to find others who have done similar testing but hardware differences could influence the results.

 

1 hour ago, Yagai said:

I mean, all it does is enabling the CPU to use all of the GPUs VRAM, right?

It can do that already, the difference being it would then be able to do it in one go. I'm not familiar with all the details, but have heard it might help or hinder depending on many variables. So if you have the setting, just try it.