AMD Ryzen 3000 and Older Zen Chips Don't Support SAM Due to Hardware Limitation, Intel Chips Since Haswell Support it

[NoJuan999]

Newest Asus ROG Strix X470-F BIOS has this Option visible in BIOS.

Version 5809
2020/12/04 14.52 MBytes
ROG STRIX X470-F GAMING BIOS 5809
"1.New CPU support
2.Offer a Re-size BAR Support option to enhance GPU performance.
3. Remove AMD 7th Gen A-series/ Athlon X4 Processors support"
ROG STRIX X470-F GAMING | ROG Strix | Gaming Motherboards｜ROG - Republic of Gamers｜ROG Singapore (asus.com)

I flashed this BIOS but I have not tested that option yet.
I have a 3700x and an RTX 2060 Super and I don't know what effect it would have.

 

[InVasMani]

Again, the same thing as with the 370x boards not supporting 5000 series processors. It turned out you can use 5000 series CPUs on 370x (with modified BIOS) and of course people say AMD lied. When is supporting same as will work with?
Same here in this situation. 3000 series probably would work with SAM but they are not supported. This probably means the gains from SAM with 3000 series are not worth it.
I'm sure Haswell will work with SAM (Intel version) but what's the point of it if it gives you nothing or a boost in an area of margin of error.
I'd rather wait for this feature release and tests its capabilities with older CPUs before jumping into any conclusions.

I'm not so certain on Haswell consider those two Broadwell quadcores with the 128MB EDRAM. In that particular case the BAR size might actually perform great in practice it might provide for a great low latency buffer to all that wider memory access. It's really one of those things that needs a degree research into to fully draw concrete conclusions about one way or another.

Newest Asus ROG Strix X470-F BIOS has this Option visible in BIOS.

Version 5809
2020/12/04 14.52 MBytes
ROG STRIX X470-F GAMING BIOS 5809
"1.New CPU support
2.Offer a Re-size BAR Support option to enhance GPU performance.
3. Remove AMD 7th Gen A-series/ Athlon X4 Processors support"
ROG STRIX X470-F GAMING | ROG Strix | Gaming Motherboards｜ROG - Republic of Gamers｜ROG Singapore (asus.com)

I flashed this BIOS but I have not tested that option yet.
I have a 3700x and an RTX 2060 Super and I don't know what effect it would have.
View attachment 178540

It's actually nice to see Asus stepping up and offering this option on this older chipset. It would be good if this becomes common by MB makers if this BAR support can be enabled on older hardware trivially. Why cripple a already present feature!? That's strange though I looked at the AsRock x470 bios and couldn't find anything to do with the BAR size itself it had a 4G decode option, but you couldn't manually adjust the BAR allocation size itself from the looks of it in the options. I wasn't certain about the "bios strings" providing clues on being adjustable and the menu and options just not present in the bios though. I didn't dig that deeply into it, but it is reasonably plausible it could be further adjustable yet there wasn't a bios string in place to do so with individual toggle options. It could be a bios where you could alter the bios string for the written in stone default bios string perhaps on the default size 256MB presumably.

 

[mirh]

BAR should be possible to resize on every PCIe 3.0 motherboard.
Performance is exactly why it may not be worth the bother eventually.

AMD doesn't seem to mind either xeons or ryzens for such things with ROCm (see my previous post)
In graphics applications though, if certain instructions are slower by two orders of magnitude you may as well try something else.

 

[ValenOne]

BAR should be possible to resize on every PCIe 3.0 motherboard.
Performance is exactly why it may not be worth the bother eventually.

AMD doesn't seem to mind either xeons or ryzens for such things with ROCm (see my previous post)
In graphics applications though, if certain instructions are slower by two orders of magnitude you may as well try something else.

From https://overclock3d.net/reviews/gpu..._on_zen_2_cpus_-_the_power_of_resizable_bar/1

AMD's SAM (resizable BAR) works (i.e. free performance increase) on Ryzen 9 3950X with ASUS ROG X570 Crosshair VIII Formula, BIOS 3003, and Radeon RX 6800 graphics card.

My ASUS ROG X570 Strix with Ryzen 9 3900X and BIOS 3001 has SAM (resizable BAR) feature on the BIOS page.

It's not about I/O or PCIe controller, it's a CPU instruction, an ISA extension of the https://en.wikipedia.org/wiki/Bit_manipulation_instruction_set. In ZEN2 it is apparently emulated in microcode using other instructions which is why it is too slow for any benefit here.

For the "Resize BAR" feature, that's not correct.

 

[mirh]

Then it was all politics all along, thanks.

Aus der Community: AMD Smart Access Memory im Test mit Radeon RX 6800

Aus der Community kommt ein Kurztest zu Smart Access Memory (SAM), dem zuletzt viel diskutierten VRAM-Vollzugriff von AMD.

www.computerbase.de

And in fact, as I hinted, it can even be enabled on older cards (one dude reported 2x performance for his 390 in cyberpunk, but it seems just too good to be true)

 

[kapone32]

I am going to check the BIOS for my X399 if there is one.

 

[ValenOne]

Then it was all politics all along, thanks.

Aus der Community: AMD Smart Access Memory im Test mit Radeon RX 6800

Aus der Community kommt ein Kurztest zu Smart Access Memory (SAM), dem zuletzt viel diskutierten VRAM-Vollzugriff von AMD.

www.computerbase.de

And in fact, as I hinted, it can even be enabled on older cards (one dude reported 2x performance for his 390 in cyberpunk, but it seems just too good to be true)

For Resize BAR, the existing RTX 3000 GPUs need a VBIOS update.

 

[Sora]

This article should have been updated when the Title content was proven to be misinformation.

 

[AsRock]

That's a bit embarrassing for AMD - introduce a new performance improving feature; limit it to new GPUs *and* new CPUs; watch the motherboard manufacturers introduce it for existing competitor CPUs....

Hopefully this will be another kick for AMD to "find a way" to introduce SAM on older AMD CPUs that are compatible with the same motherboards that support the latest AMD CPUs.

Then the people have to speak louder.

 

[ValenOne]

It's not about I/O or PCIe controller, it's a CPU instruction, an ISA extension of the https://en.wikipedia.org/wiki/Bit_manipulation_instruction_set. In ZEN2 it is apparently emulated in microcode using other instructions which is why it is too slow for any benefit here.

That's wrong. Read https://www.techpowerup.com/279264/...ry-resizable-bar-support-to-ryzen-3000-series

AMD officially supports Smart Access Memory (resizable base address register) for Ryzen 3000 series "Matisse" processors, based on the "Zen 2" microarchitecture. LOL

This article should have been updated when the Title content was proven to be misinformation.

The news content was ultimately proven to be fake news.

 

[AsRock]

Sadly not being able to get a frigging card it makes little difference, never mind it only being 1-2% lmao.

That's wrong. Read https://www.techpowerup.com/279264/...ry-resizable-bar-support-to-ryzen-3000-series

AMD officially supports Smart Access Memory (resizable base address register) for Ryzen 3000 series "Matisse" processors, based on the "Zen 2" microarchitecture. LOL


The news content was ultimately proven to be fake news.

would love to be able try but no chance of that, the option on my MB is greyed out.

 

[ValenOne]

Sadly not being able to get a frigging card it makes little difference, never mind it only being 1-2% lmao.





would love to be able try but no chance of that, the option on my MB is greyed out.

I assume your AMD4 motherboard is an Asrock B450 Pro4

From http://www.asrock.com/MB/AMD/B450 Pro4/#BIOS
The latest BIOS date is Nov 19, 2020, which is old.

ROG Strix X570-F Gaming | ROG Strix | Gaming Motherboards｜ROG - Republic of Gamers｜ROG Australia

AMD Ryzen 3000 series ATX motherboard with Aura Sync, Intel Gigabit LAN, Dual PCIe 4.0 M.2 with heatsinks, SupremeFX and USB 3.2 Gen 2

rog.asus.com

My motherboard's BIOS supports up to AM4 AGESA V2 PI 1.2.0.0.

 

[AsRock]

I assume your AMD4 motherboard is an Asrock B450 Pro4

From http://www.asrock.com/MB/AMD/B450 Pro4/#BIOS
The latest BIOS date is Nov 19, 2020, which is old.

ROG Strix X570-F Gaming | ROG Strix | Gaming Motherboards｜ROG - Republic of Gamers｜ROG Australia

AMD Ryzen 3000 series ATX motherboard with Aura Sync, Intel Gigabit LAN, Dual PCIe 4.0 M.2 with heatsinks, SupremeFX and USB 3.2 Gen 2

rog.asus.com

My motherboard's BIOS supports up to AM4 AGESA V2 PI 1.2.0.0.

Not sure if the B550 pro4 has the option but the X570 Pro 4 does, why assume when you could of asked if i had a 550 or 570 MB.

And yes i corrected it so no one else assumes.

 

[kapone32]

I assume your AMD4 motherboard is an Asrock B450 Pro4

From http://www.asrock.com/MB/AMD/B450 Pro4/#BIOS
The latest BIOS date is Nov 19, 2020, which is old.

ROG Strix X570-F Gaming | ROG Strix | Gaming Motherboards｜ROG - Republic of Gamers｜ROG Australia

AMD Ryzen 3000 series ATX motherboard with Aura Sync, Intel Gigabit LAN, Dual PCIe 4.0 M.2 with heatsinks, SupremeFX and USB 3.2 Gen 2

rog.asus.com

My motherboard's BIOS supports up to AM4 AGESA V2 PI 1.2.0.0.

Every MSI board that I have B450, B550 and X570 have Re size bar support in the BIOS. It is actually in the exact same place.