EXPERIMENTAL: Resizable BAR in DCS for NVIDIA RTX 30 Series GPUs

[speed-of-heat]

Yes, and just turned it on in bios, afaik the settings are not available in profile inspector on the latest drivers

[Snacko]

Just wondering if there are any updates on this?  I have everything flashed and updated and setup but I see no improvement.  I've seen on other games that they had an option within the game to enable Rebar.  I don't remember which game.  But maybe there is something in DCS that excludes ReBar?  

[5ephir0th]

On 10/12/2022 at 10:21 PM, Snacko said:

Just wondering if there are any updates on this?  I have everything flashed and updated and setup but I see no improvement.  I've seen on other games that they had an option within the game to enable Rebar.  I don't remember which game.  But maybe there is something in DCS that excludes ReBar?  

ReBar has to be supported by game engine, DCS has not be updated to support it

[Camble]

On 10/14/2022 at 5:23 PM, 5ephir0th said:

ReBar has to be supported by game engine

I'm not sure this is true. Results may vary between games, but it basically just expands how much of the frame buffer the CPU can access at once.

[Hoirtel]

8 hours ago, Camble said:

I'm not sure this is true. Results may vary between games, but it basically just expands how much of the frame buffer the CPU can access at once.

I think it's more down to Nvidia, when rebar first came out a few of us were manually enabling it in profile inspector and it was helping smooth things out. Then one driver update locked it down, unsure where it's at these days. I think all those conversations will be the history in this thread. 

[Mustang]

Thread bump, new version of nVidia Profile Inspector is out with more direct control of Rebar (options are inside the 'Common' section of the app)

https://github.com/Orbmu2k/nvidiaProfileInspector/releases/tag/2.4.0.2

Edited November 20, 2022 by Mustang

[Hoirtel]

1 hour ago, Mustang said:

Thread bump, new version of nVidia Profile Inspector is out with more direct control of Rebar (options are inside the 'Common' section of the app)

https://github.com/Orbmu2k/nvidiaProfileInspector/releases/tag/2.4.0.2

 

Hmm. Does this mean an unlocking of this as a feature? The previous options were always there but stopped making a difference with a single drive update. 

Edited November 20, 2022 by Hoirtel

[MHAce75]

had previously posted in 4090 thread on the matter. I just tried it again with rebar enabled and nvidiaprofileinspector rBar - Feature enabled, rBar - 0x00000001 (profile description says "Battlefield, etc." and rBar - Size Limit also... 

it definitely does something, GPU ms went over 15ms (from previously 0 to 9ms) and all artefacts I had observed prior disappeared (especially visible in external view F3, when the plan flies towards you) however, heavy stuttering especially when looking to right or left (loss of smooth motion). 

Then I wondered whether i should change something in OTT (e.g. modfiy "Default ASW Mode" to something different than 45Hz forced), but then my PC crashed and rebooted --- either overheating (which I believe i had observed earlier, hence my post in the 4090 thread) or because under such load, CPU couldn't handle my slight undervolting values in ThrottleStop... might also be that my prebuilt MSI MEG Infinite XTE just can't handle it, even though I swapped to a 1000w MSI PSU and 64GB Corsair RAM...

Definitely worth a few more tries with Rebar enabled, thought. Will remove undervolt and try to play with OTT or OXRTK as long as my gear allows. If it crashes then again its most likely due to overheating (stock water cooler... yikes)... 

[diamond26]

2 hours ago, MHAce75 said:

had previously posted in 4090 thread on the matter. I just tried it again with rebar enabled and nvidiaprofileinspector rBar - Feature enabled, rBar - 0x00000001 (profile description says "Battlefield, etc." and rBar - Size Limit also... 

it definitely does something, GPU ms went over 15ms (from previously 0 to 9ms) and all artefacts I had observed prior disappeared (especially visible in external view F3, when the plan flies towards you) however, heavy stuttering especially when looking to right or left (loss of smooth motion). 

Then I wondered whether i should change something in OTT (e.g. modfiy "Default ASW Mode" to something different than 45Hz forced), but then my PC crashed and rebooted --- either overheating (which I believe i had observed earlier, hence my post in the 4090 thread) or because under such load, CPU couldn't handle my slight undervolting values in ThrottleStop... might also be that my prebuilt MSI MEG Infinite XTE just can't handle it, even though I swapped to a 1000w MSI PSU and 64GB Corsair RAM...

Definitely worth a few more tries with Rebar enabled, thought. Will remove undervolt and try to play with OTT or OXRTK as long as my gear allows. If it crashes then again its most likely due to overheating (stock water cooler... yikes)... 

Just a note on the use of ASW in Q2. The GPU usage is lower whenever I use 45 forced or locked compared to ASW disabled. (rebar is enabled)

[MHAce75]

interestingly, with native OpenXR I now get better results with OXTK Turbo On with ASW 45, or Auto/Adaptive, but not with 45 forced (stutters/no smooth movement)... quite different than before. Which is strange, because OXTK says Turbo On "disables" ASW... 

vor 2 Stunden schrieb diamond26:

Just a note on the use of ASW in Q2. The GPU usage is lower whenever I use 45 forced or locked compared to ASW disabled. (rebar is enabled)

no cpu overheating issue with rebar? or at least observed hotter cpu? ... 

[diamond26]

2 hours ago, MHAce75 said:

interestingly, with native OpenXR I now get better results with OXTK Turbo On with ASW 45, or Auto/Adaptive, but not with 45 forced (stutters/no smooth movement)... quite different than before. Which is strange, because OXTK says Turbo On "disables" ASW... 

no cpu overheating issue with rebar? or at least observed hotter cpu? ... 

I have noticed that for Quest2, Turbo ON works with all ASW different settings.

I have no impact on CPU temperatures because of rebar

[HemiGuy]

I am now running a new 4090 on an intel i9 CPU build.  Wondering if the new DCS OB that now has Mult-Threading change the recommendation to enable resizable Bar using the NVIDIA Profile Inspector tool?  Still recommended or not needed?

[WipeUout]

I think it is still not implemented in DCS.  If you enable it, the little gear next to the feature in nvidia inspector remains blue.  If a feature is enable, the gear should turn green.

[Fakum]

Im in the process of a new build and stumbled across some comments about this Resizing BAR, so I did some digging to get educated. The shorter version of my findings are that I learned alot just from this video. A few things that I got out of it were:

-You can manually turn it on for DCS

-It does take a bit of the load off of the CPU when enabled

-Reading through the comments though, it may have a negative impact in DCS and although it MAY increase your FPS slightly, it may also be creating more latency between frames resulting in more FPS, but more stuttering.

 

[Hoirtel]

On 4/19/2023 at 9:29 PM, Fakum said:

Im in the process of a new build and stumbled across some comments about this Resizing BAR, so I did some digging to get educated. The shorter version of my findings are that I learned alot just from this video. A few things that I got out of it were:

-You can manually turn it on for DCS

-It does take a bit of the load off of the CPU when enabled

-Reading through the comments though, it may have a negative impact in DCS and although it MAY increase your FPS slightly, it may also be creating more latency between frames resulting in more FPS, but more stuttering.

 

The current status as as far as I was aware remains unchanged and that it is not available for use in DCS even if enabled manually. This is because Nvidia has locked it to compatible titles or whatever the commercial agreement is. 

Prior to lockdown it did improve smoothness for me in VR, no FPS increase but good reduction in ground stuttering. I could literally switch it off and on with completely repeatable results. This was on a much older version of DCS, maybe an early 2.7. Then one Nvidia driver locked it, and on or off performed just like off. Rolled back to old driver and it was smooth again. I have since moved on to the many GPU driver updates since then and DCS has had a lot of change in this time too. I continue to run with rebar enabled and see no difference in DCS with it on or off, suggesting it is still locked.

[javelina1]

by default whenever I update the nVidia driver, I just automatically make the BAR edit in my DCS profile.  Whether helps or not at this point, I don't know.  (I do it for the other WWII sim and the Civ sim as well...)

[WipeUout]

16 hours ago, javelina1 said:

Whether helps or not at this point, I don't know.

Activating RBAR will have different outcome depending on the game.  It may not in all cases improve FPS but it can reduce stutters or improve stability.

The easy way to see if the feature is active or not is to use nvidia profile inspector.  Select the game profile and scroll down to section 5.  There is a small gear icon beside each selectable features. If it is gray, it is not activated and you can toggle it.  If it is blue, then it is activated but not necessarily supported by the game.  If the icon is green, then the feature is active and supported by the specific game.  For DCS, the feature is still not supported unfortunately.