Can Resizable BAR Support be ported to older Intel Chipsets?

davidm71 · February 27, 2021, 7:44pm

Isnt this feature only beneficial if you have a 3000 nvidia series or AMD 6000 series card? Fwiw if modders (like Dsanke) can backport the bios of an Apex X onto an Apex IX I would imagine its possible if the board is similar? Also love to see the memory of sli cards combined. Wonder if thats even possible?

Thanks

onuracengiz · February 27, 2021, 8:19pm

The feature will require a motherboard/processor combo that supports Resizable BAR, a supported BIOS (&vbios) and a graphics card (&driver) that supports the PCIe Resizable BAR function
If i recall correctly, MSI already has enabled support for a wide range of motherboards, Intel 500-series, 400-series and 300-series chipsets and AMD TRX40, X570, B550, A520, X470 and B450 etc
Fyi,AMD has a different name for this,Smart Access Memory.and just like AMD’s implementation,Resizable BAR gives the processor access to the VRAM on the graphics cards

Graphics cards usually have a limitation of amount of VRAM that is accessible by the processor. He limit is 256MB of VRAM memory for the buffer running under the PCI bus.

Under the 256MB limit, the GPU firmware and operating system dictated its use. A VRAM memory space that was left to the processor’s free access.

It was on January 22, 2008 when the capacity was proposed Resizable BAR, which would be admitted on April 24, 2008. This technology is integrated within the PCI Express 3.0 standard.

This technology allows the processor can access all the VRAM memory. The only restriction is imposed by the GPU and the amount of VRAM you need to load textures and other elements.

As an anecdote, who proposed this solution were Hewlett-Packard and Advanced Micro Devices, come on, HP and AMD. Both companies were the ones that presented the idea to PCI-SIG, who manages the PCI Express standard

davidm71 · February 27, 2021, 8:25pm

Just checked Gigabytes support site and they have a BAR supported bios available for the Z390 Master. Would get no benefit considering I have 1080 gpus in there and have a completely stable system.

Anyhow all my fellow Gigabyte fan boys over at Overclock should be happy!

Edit: After researching this out have discovered the other half of the problem especially those of us with older cards is that if not for lack of corporate interest these old card could support SAM/BAR if the drivers allowed it. This is because I’m getting reports on other forums that in Linux environment it works. That SAM or BAR works with older cards but only in Linux. This makes me wonder if the Windows drivers can be hacked. Possibly not easily at the very least. If only the big gpu makers would just be generous and unlock it for everyone to take advantage of…

Soul1 · March 2, 2021, 5:44pm

CPU does not need to support RBAR. RBAR is purely a motherboard to GPU interface. CPU only has to support 64bit BAR to take advantage of it.

However the motherboard, GPU, GPU Driver, and OS need to be able to support RBAR to take advantage of it.

Intel has supported full 64bit BAR since Haswell, and you can use Vega with 4790k in Linux to see entire GPU memory as addressable even today. All we are missing is the negotiation code, rather than MOBO assuming 256MB transfer chunks. That is it.

And no this does not require PCIe4.0, RBAR was introduced in 2016 as an optional feature for PCIe3.0. Please inform yourself and read some white papers first.

davidm71 · March 2, 2021, 6:55pm

Is that negotiation code on the rom of the gpu or in the driver?

Dataschock · March 2, 2021, 7:40pm

Here you can find a H310 beta for this:
https://de.msi.com/Motherboard/support/H310I-PRO

Soul1 · March 2, 2021, 8:24pm

Is that negotiation code on the rom of the gpu or in the driver?

Code is required on Mobo, GPU ROM, Driver and OS. All 4 have to support it in their own code. Windows has supported since 2017.

A quick way to take a top down view is:
1. OS allows this communication to applications,
2. GPU driver allows this communication between OS and GPU,
3. and GPU ROM allows communication to Mobo to adjust the transfer unit
4. Mobo code adjusts its PCIe transfer unit settings

This is how I understood it works. It is a chain of command, and everyone in the chain has to have the code to support it.

Nvidia GPU BIOS update will be provided shortly to support it, GPU Driver with support will come along side and OS already supports it. So, the only component missing for us is Mobo BIOS.

davidm71 · March 2, 2021, 9:58pm

Yeah but the million dollar question is do gpu’s since 1080 or 2080 series already have that code?

Kamiccolo · March 6, 2021, 12:22am

I have seen Resizable Bar is inside my msi godlike gaming carbon bios. x99a gonna try to enable it when i get my 3090 here.

davidm71 · March 6, 2021, 2:45am

Read that despite that Intel is limiting it to 10th and 11th gen cpu’s. Not sure but read it somewhere.

Soul1 · March 10, 2021, 7:40pm

They dont, as nVidia has never looked into it till now. Even 3xxx vBIOS doesnt have that code, but nVidia will implement it now. So, unless they implement it for older GPUs via vBIOS updates, it will not happen for older chips.

chinobino · March 13, 2021, 11:07pm

The first (Beta) Z370 BIOS with Resizable BAR Support has been released by EVGA for the Z370 Classified K.

Location in AMIBCP;

AMIBCP Z370 Classified K Resizable BAR Support Location.png

I can see changes to Setup (GUID 899407D7-99FE-43D8-9A21-79EC328CAC21), specifically;

PCIe Configuration → ‘Above 4G Memory Assignment’ has been added
PCIe Configuration → ‘Resizable BAR Support’ has also been added

0x540E0 Form: PCIe Configuration, FormId: 0x2847 {01 86 47 28 B3 17}
0x540E6 Subtitle: Statement.Prompt: PCIe Configuration, Flags: 0x0 {02 87 B3 17 00 00 00}
0x540ED End {29 02}
0x540EF Suppress If {0A 82}
0x540F1 QuestionId: 0x273A equals value 0xF {12 06 3A 27 0F 00}
0x540F7 One Of: Above 4G Memory Assignment, VarStoreInfo (VarOffset/VarName): 0x7EE, VarStore: 0x1, QuestionId: 0x2848, Size: 1, Min: 0x0, Max 0x1, Step: 0x0 {05 91 5B 19 5C 19 48 28 01 00 EE 07 14 10 00 01 00}
0x54108 One Of Option: Enabled, Value (8 bit): 0x1 {09 07 8D 00 00 00 01}
0x5410F One Of Option: Disabled, Value (8 bit): 0x0 (default) {09 07 8E 00 30 00 00}
0x54116 End One Of {29 02}
0x54118 End If {29 02}
0x5411A One Of: Resizable BAR Support, VarStoreInfo (VarOffset/VarName): 0xFFC, VarStore: 0x1, QuestionId: 0x2849, Size: 1, Min: 0x0, Max 0x1, Step: 0x0 {05 91 C7 14 C8 14 49 28 01 00 FC 0F 14 10 00 01 00}
0x5412B One Of Option: Disabled, Value (8 bit): 0x0 {09 07 04 00 00 00 00}
0x54132 One Of Option: Enabled, Value (8 bit): 0x1 {09 07 03 00 00 00 01}
0x54139 Default: DefaultId: 0x0, Value (8 bit): 0x0 {5B 06 00 00 00 00}
0x5413F Default: DefaultId: 0x1, Value (8 bit): 0x0 {5B 06 01 00 00 00}
0x54145 End One Of {29 02}

There is also modifications to PciDynamicSetup (GUID 2CE5604F-A982-4D2E-8FD0-D1600C2E1515)

0x60D7 Checkbox: Above 4G Decoding, VarStoreInfo (VarOffset/VarName): 0x3, VarStore: 0xCCCC, QuestionId: 0x7006 {06 8E 0C 00 0D 00 06 70 CC CC 03 00 10 00}
0x60E5 Default: DefaultId: 0x0, Value (8 bit): 0x1 {5B 06 00 00 00 01}
0x60EB End {29 02}
0x60ED Checkbox: Resizable BAR Support, VarStoreInfo (VarOffset/VarName): 0x4, VarStore: 0xCCCC, QuestionId: 0x702B {06 8E CC 00 CD 00 2B 70 CC CC 04 00 10 00}
0x60FB Default: DefaultId: 0x0, Value (8 bit): 0x0 {5B 06 00 00 00 00}
0x6101 End {29 02}

Unfortunately I only have a 2070 (Turing) GPU so I can’t test it.

davidm71 · March 13, 2021, 11:18pm

I don’t understand the point in Z370 or Z390 support as I understand Intel has locked RBar support to 10th and 11th gen CPU’s unless of course motherboard manufacturers wouldn’t waste a dime unless they knew Intel would go with 8th or 9th gen support as well?

Feyd1364 · March 14, 2021, 12:35pm

From what I understand Resizable BAR is technically viable on Haswell (4th gen) and newer CPUs. Only thing missing right now is support in EFI.

onuracengiz · March 14, 2021, 1:37pm

onuracengiz:

The feature will require a motherboard/processor combo that supports Resizable BAR, a supported BIOS (&vbios) and a graphics card (&driver) that supports the PCIe Resizable BAR function
If i recall correctly, MSI already has enabled support for a wide range of motherboards, Intel 500-series, 400-series and 300-series chipsets and AMD TRX40, X570, B550, A520, X470 and B450 etc
Fyi,AMD has a different name for this,Smart Access Memory.and just like AMD’s implementation,Resizable BAR gives the processor access to the VRAM on the graphics cards
Graphics cards usually have a limitation of amount of VRAM that is accessible by the processor. He limit is 256MB of VRAM memory for the buffer running under the PCI bus.

Under the 256MB limit, the GPU firmware and operating system dictated its use. A VRAM memory space that was left to the processor’s free access.

It was on January 22, 2008 when the capacity was proposed Resizable BAR, which would be admitted on April 24, 2008. This technology is integrated within the PCI Express 3.0 standard.

This technology allows the processor can access all the VRAM memory. The only restriction is imposed by the GPU and the amount of VRAM you need to load textures and other elements.

As an anecdote, who proposed this solution were Hewlett-Packard and Advanced Micro Devices, come on, HP and AMD. Both companies were the ones that presented the idea to PCI-SIG, who manages the PCI Express standard

I quote here;
With the release of our newest GeForce Game Ready Driver (461.72) on February 25th, 2021, we’re enabling our initial Resizable BAR support on GeForce RTX 3060 graphics cards and in the following titles:

Motherboards:

AMD 400 Series
AMD 500 Series
Intel Z490
Intel H470
Intel B460
Intel H410
All motherboards that support 11th-gen Intel processors

CPUs:

AMD Ryzen 3 5xxx
AMD Ryzen 5 5xxx
AMD Ryzen 7 5xxx
AMD Ryzen 9 5xxx
Intel Core i9-10xxx
Intel Core i7-10xxx
Intel Core i5-10xxx
Intel Core i3-10xxx
Intel Core i9-11xxx
Intel Core i7-11xxx
Intel Core i5-11xxx

They have also announced DLSS same day with a promise for older card(s) support,but nothing new yet
Note:The Haswell architecture released in 2013 already had support for Resizable BAR.

Deep learning super sampling.DLSS forces a game to render at a lower resolution (typically 1440p) and then uses its trained A.I. algorithm to infer what it would look like if it were rendered at a higher one (typically 4K). It does this by utilizing some anti-aliasing effects (likely Nvidia’s own TAA) and some automated sharpening. Visual artifacts that wouldn’t be present at higher resolutions are also ironed out and even used to infer the details that should be present in an image.In effect, DLSS is a real-time version of Nvidia’s screenshot-enhancing Ansel technology. It renders the image at a lower resolution to provide a performance boost, then applies various effects to deliver a relatively comparable overall effect to raising the resolution.DLSS 2.0 feature is only compatible with 15 games. That’s less than the number of games that support ray tracing

X99-Freak · March 15, 2021, 2:21pm

Maybe i could help with some testing if an unusual but interesting system is needed.

Intel Xeon E5 2699 v3
Asrock X99 Extreme11
Gigabyte RX 6900 XT
Win10

I would test it

No risc no fun.

Squall_Leonhart · March 16, 2021, 3:35am

PDEP/PEXT has nothing to do with Resizable bar.

panosxidis · March 18, 2021, 7:58pm

on AMIBCP your mobo only has 4G Deconding above same like me on ASUS RAMPAGE V

panosxidis · March 18, 2021, 8:21pm

onuracengiz:

Zitat von onuracengiz im Beitrag #22
The feature will require a motherboard/processor combo that supports Resizable BAR, a supported BIOS (&vbios) and a graphics card (&driver) that supports the PCIe Resizable BAR function
If i recall correctly, MSI already has enabled support for a wide range of motherboards, Intel 500-series, 400-series and 300-series chipsets and AMD TRX40, X570, B550, A520, X470 and B450 etc
Fyi,AMD has a different name for this,Smart Access Memory.and just like AMD’s implementation,Resizable BAR gives the processor access to the VRAM on the graphics cards
Graphics cards usually have a limitation of amount of VRAM that is accessible by the processor. He limit is 256MB of VRAM memory for the buffer running under the PCI bus.

Under the 256MB limit, the GPU firmware and operating system dictated its use. A VRAM memory space that was left to the processor's free access.

It was on January 22, 2008 when the capacity was proposed Resizable BAR, which would be admitted on April 24, 2008. This technology is integrated within the PCI Express 3.0 standard.

This technology allows the processor can access all the VRAM memory. The only restriction is imposed by the GPU and the amount of VRAM you need to load textures and other elements.

As an anecdote, who proposed this solution were Hewlett-Packard and Advanced Micro Devices, come on, HP and AMD. Both companies were the ones that presented the idea to PCI-SIG, who manages the PCI Express standard

I quote here;
With the release of our newest GeForce Game Ready Driver (461.72) on February 25th, 2021, we’re enabling our initial Resizable BAR support on GeForce RTX 3060 graphics cards and in the following titles:

Motherboards:

AMD 400 Series
AMD 500 Series
Intel Z490
Intel H470
Intel B460
Intel H410
All motherboards that support 11th-gen Intel processors

CPUs:

AMD Ryzen 3 5xxx
AMD Ryzen 5 5xxx
AMD Ryzen 7 5xxx
AMD Ryzen 9 5xxx
Intel Core i9-10xxx
Intel Core i7-10xxx
Intel Core i5-10xxx
Intel Core i3-10xxx
Intel Core i9-11xxx
Intel Core i7-11xxx
Intel Core i5-11xxx

They have also announced DLSS same day with a promise for older card(s) support,but nothing new yet
Note:The Haswell architecture released in 2013 already had support for Resizable BAR.

Deep learning super sampling.DLSS forces a game to render at a lower resolution (typically 1440p) and then uses its trained A.I. algorithm to infer what it would look like if it were rendered at a higher one (typically 4K). It does this by utilizing some anti-aliasing effects (likely Nvidia’s own TAA) and some automated sharpening. Visual artifacts that wouldn’t be present at higher resolutions are also ironed out and even used to infer the details that should be present in an image.In effect, DLSS is a real-time version of Nvidia’s screenshot-enhancing Ansel technology. It renders the image at a lower resolution to provide a performance boost, then applies various effects to deliver a relatively comparable overall effect to raising the resolution.DLSS 2.0 feature is only compatible with 15 games. That’s less than the number of games that support ray tracing

ON MINE ASUS RAMPAGE V X99 with 6950X i have only 4G Deconding above on AMIBCP so he saying Haswell and up supports resizable bar so i dont know what happen

chinobino · March 23, 2021, 5:03am