On or off for msfs2024? RTX3080 and 5800X3D

Stuff I've been reading suggests that I might use less VRAM turning it off either in the BIOS or with Nvidia Inspector.

Any thoughts or pearls of wisdom from anyone who may have explored this subject more deeply?

I've seen those comments some time ago. I disabled rebar with negative results and re-enabled.

Perhaps there is something in the PC bios that is different in the many systems out there.

From the benchmarks I've seen, you may gain an extra frame or two with it on. That said, the Xbox has resizable bar, so MSFS is likely developed with the option turned on.

I tested it by looking at VRAM usage and I didn't see any difference with it on or off. Maybe it depends on how much VRAM your card has.

 

I'm participating to this long thread on the official forum and a lot of users, including myself, gains +1Gb of VRAM when Resizable Bar is OFF. No impact on performance, for my usage and my PC configuration.

But we all know that each PC configuration is different.

1 hour ago, vbazillio said:

I'm participating to this long thread on the official forum and a lot of users, including myself, gains +1Gb of VRAM when Resizable Bar is OFF. No impact on performance, for my usage and my PC configuration.

But we all know that each PC configuration is different.

I also gain +1 to 1.5Gb vram with rebar turned off in bios, with no performance hit

There is something fundamentally wrong with the Asobo code if the average User has to go into BIOS to change a setting, this isn't something anyone should have to do. Resizeable Bar is supposed to help graphical performance in video games, so Asobo need to find out why it acts this way with theirs and fix it.

Now of course not everyones PCs are identical, there will be separate use cases where turning it "Off" will have a positive effect so it's a definite "Your Mileage May Vary" type of setting. Just remember to turn in back "On" should Asobo find the root cause of what is a big issue here.
(on my Gigabyte Aorus Mobo I only get the options of Disabled & Auto, neither makes any difference and seeing as I play other games/sims that benefit from this Technology I leave mine "On/Auto")

Some info from nVidia;
Resizable BAR utilizes an advanced feature of PCI Express to increase performance in certain games. As of March 30th, 2021, Resizable BAR is supported for GeForce RTX 30 Series graphics cards and laptops.

Resizable BAR is an optional PCI Express interface technology. As you move through a world in a game, GPU memory (VRAM) constantly transfers textures, shaders and geometry via many small CPU to GPU transfers.

With the ever-growing size of modern game assets, this results in a lot of transfers. Using Resizable BAR, assets can instead be requested as-needed and sent in full, so the CPU can efficiently access the entire frame buffer. And if multiple requests are made, transfers can occur concurrently, rather than queuing. 

1 hour ago, MarcG said:

There is something fundamentally wrong with the Asobo code if the average User has to go into BIOS to change a setting, this isn't something anyone should have to do. Resizeable Bar is supposed to help graphical performance in video games, so Asobo need to find out why it acts this way with theirs and fix it.

Now of course not everyones PCs are identical, there will be separate use cases where turning it "Off" will have a positive effect so it's a definite "Your Mileage May Vary" type of setting. Just remember to turn in back "On" should Asobo find the root cause of what is a big issue here.
(on my Gigabyte Aorus Mobo I only get the options of Disabled & Auto, neither makes any difference and seeing as I play other games/sims that benefit from this Technology I leave mine "On/Auto")

Some info from nVidia;
Resizable BAR utilizes an advanced feature of PCI Express to increase performance in certain games. As of March 30th, 2021, Resizable BAR is supported for GeForce RTX 30 Series graphics cards and laptops.

Resizable BAR is an optional PCI Express interface technology. As you move through a world in a game, GPU memory (VRAM) constantly transfers textures, shaders and geometry via many small CPU to GPU transfers.

With the ever-growing size of modern game assets, this results in a lot of transfers. Using Resizable BAR, assets can instead be requested as-needed and sent in full, so the CPU can efficiently access the entire frame buffer. And if multiple requests are made, transfers can occur concurrently, rather than queuing. 

You can use NVIDIA Profile Inspector to disable it, but do it within the game setting not global setting. 

Edited May 3, 20251 yr by Gulf76

3 minutes ago, Gulf76 said:

First of all, Resizeable Bar has nothing to do with Asobo so get off your soapbox. Second, it’s enabled by default in BIOS on most newer systems. Lastly, you can use NVIDIA Profile Inspector to disable it, but do it within the game setting not global setting. 

I know the technology has nothing to do with Asobo, what I very clearly said was that it's up to Asobo to improve their code for it so that their software works better with it turned "On".

It's quite simple to understand really.

As a UK pensioner (sorry, I meant peasant) with limited funds, I have to make the best of what I have, i.e., a 5-year-old MB, 32 gig RAM, and an aging 3060. Firstly, I had to switch on rBAR in my BIOS, I then used Profile Inspector to activate it in Windows. I also joined Win11 beta and upgraded to 24h2 which enabled DirectStorage 2.0 on my main C:/ drive. Overall these tweaks have made an enormous difference along with AutoFPS and the Frame Gen Mod (MSFS2020) in 2024 I use the AMD FG, which is now enabled.

RBar off with Profile Inspector made condition worse in 2024 Beta, VR Mode with 5090. Very happy it appears to help many.

1 hour ago, Erv Moore said:

RBar off with Profile Inspector made condition worse in 2024 Beta, VR Mode with 5090. Very happy it appears to help many.

Same here with 4090 and Crystal OG! Maybe it’s helpful turned off for those with lower tier GPU’s with limited VRAM. 

Edited May 3, 20251 yr by Gulf76

1 hour ago, Gulf76 said:

Same here with 4090 and Crystal OG! Maybe it’s helpful turned off for those with lower tier GPU’s with limited VRAM. 

I think this is the point.

The computer has to process a certain number of operations to play the game. With ReBar you let the GPU do more of those operations (hence increased Vram), and offload the CPU.

If you have the Vram just let the GPU handle those operations and let the CPU cause less stutter or do other stuff, such as increased TLOD or more AI traffic.

Edited May 3, 20251 yr by LGKR

When I was looking into ways to salvage some of my limited 12GB of Vram on the 3080ti I came across posts and videos about ReBar.  I have used it for some time, enabled in the BIOS, confirmed as active in nVidia Control Panel and enabled in the MSFS2024 inspector profile.  First of all I disabled it in Inspector but my gpu was still getting hammered despite being on medium settings using the Fenix.  Resolution is 4K but using DLSS (Quality).  AutoFPS was often reducing many of my settings to Low or even off to save Vram.  I ended up disabling it completely in the BIOS but not tested properly.  I dont use overlays etc so not sure how much vram is being actually used. AutoFPS however does tell you when its near its % limits

Nv inspector specifically mentions msfs 2024 in rebar