A Reddit user has posted their results of manually enabling Resizable BAR for Dead Space and reported impressive results. While Resizable BAR might be on by default for some motherboards it is always worth checking your BIOS to be sure. It is also worth noting that the feature is not always on automatically for every game and this can be due to it not yet having been added to NVIDIA’s whitelist of compatible games via a driver update. However, it is possible to manually enable Resizable BAR with NVIDIA Profile Inspector.
Reddit user sxKYLE has posted screenshots of their results in turning on the feature for the barely one-week-old game. Resizable BAR is an optional PCI Express interface technology that can allow assets to be fully loaded to the frame buffer and thus improve performance in certain games. The feature was first introduced with NVIDIA’s RTX 30-series graphics cards. Performance gains will vary and it does require compatible hardware to be used.
What Is Resizable BAR (via NVIDIA)
“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.“
When it was introduced and tested on an NVIDIA GeForce RTX 3080 there were gains of up to 12 percent so it should come as no surprise that an NVIDIA GeForce RTX 4080, with its improved architecture, could easily surpass that mark. In this particular scenario, an Intel i7 9700K was used with an RTX 4080 while testing the feature at a 21:9 ultrawide resolution of 3440×1440 where average framerates jumped from 76 FPS up to 111 FPS.
Why it is not automatically on for every game
A number of users have asked in the thread why NVIDIA doesn’t just have it turned on by default and an NVIDIA Forums Representative responded to the question by explaining that there’s more to it than that.
“It is not so straightforward. We test games across multiple levels and across each new build of a game before release. So while some users may see a bump in performance in one level/map, if you try a different level/map, the game assets might be quite different and users may not benefit as much or worse experience a regression in FPS/frame times.
As for the Dead Space remake, we are still testing ReBAR performance so there is a chance we may enable it in a future driver.
For those who are not familiar with Resizable BAR, I encourage you to read our GeForce.com article on this subject:
https://www.nvidia.com/en-us/geforce/news/geforce-rtx-30-series-resizable-bar-support“
So while enabling Resizable BAR manually may provide impressive results it may not be consistent, or stable, depending on how a game is designed. Other users in the thread also noted that video cards with less VRAM may have issues if the game demands more memory than a card has while the feature is on.