Lower performance on ARC A750 with Rebar on?

[Wheeledion]

Hi!!

Was wondering if anyone has faced similar issues where in-game performance is actually impacted negatively when turning on Rebar?

Firstly my specs:
R5 5600
Arc A750
Asrock B450m HDV (most likely culprit idk)
Gigabyte m.2 nvme
driver version: 5445

My problem is as follows: When I turn on Rebar, some games have the desired output, whereas most games struggle immensely to consistently meet par.

Games that struggle right off the bat are
Spiderman Remastered
Uncharted
Elden Ring

No matter what I do in these games, however much I tweak with the settings the GPU stays at 40% utilization and at around 1000mhz as a result I get 20-30 fps in these titles. Sony titles are the worst offenders where they give me playable frames when I'm looking away from the action.
However once I disabled both resize bar and above 4g decoding these games gave me a consistent 70-80fps with Elden ring reaching 55-60 as expected.

However the most mind boggling thing is that some games actually do perform up to spec up until I perform a very specific set of actions. With Rebar on in God of war I can expect somewhere around 110FPS (using dxvk btw) but if I look at a "heavy" to load area the GPU problem rears it's ugly head.
Eg. standing under/ next to the Vanaheim tower (on a boat); if you were to look at the temple/bridge the FPS takes a massive hit and goes down to 50. In fact performance takes a hit if you look at the temple from any area while on the lake of nine.

Funnily enough timespy and all the other benchmarks are working fine for me with rebar on. It's just these specific games that are causing problems for me specifically, because as far as I can tell online people are getting better results in the aforementioned games I am struggling with. I believe it may just be a result of poor implementation of rebar by asrock?

Would love to get some assistance regarding the same, thanks!

[ShunMnzed]

Hi wheel. ReBAR is designed to improve performance by allowing the CPU to access the full GPU memory space, but its effectiveness can vary depending on the game and system configuration.

Given your specs, there are a few factors to consider, The Asrock B450m HDV motherboard may have limitations with ReBAR support. While ASRock has enabled ReBAR on some B450 motherboards, it's crucial to ensure that your specific motherboard model supports it and that you have the latest BIOS update installed. Not all games benefit from ReBAR, and some may even experience performance issues when it's enabled. This seems to be the case with the games you mentioned, where disabling ReBAR improves performance. It's also possible that these games have not been optimized for ReBAR, leading to the issues you're facing. Driver updates often include optimizations for new technologies like ReBAR, which could resolve some of the performance inconsistencies. Other system components, such as the CPU or storage, could also be contributing to the performance issues. However, since you're seeing improvements with ReBAR off, this is less likely to be the cause. The low GPU utilization you're experiencing suggests that the GPU is not being fully leveraged with ReBAR on. This could be due to the way ReBAR is implemented in your system or how the games interact with it.

You can try the following:

1. Check for a BIOS update for your motherboard that might improve ReBAR compatibility and performance.
2. Some games may have specific settings or patches that improve ReBAR performance. Look for any game-specific updates.
3. Make sure your GPU drivers are up to date. Intel frequently releases updates that could improve ReBAR performance.

ReBAR is still a relatively new technology, and its implementation can vary. It's not uncommon for some systems to experience issues like the ones you're facing. Hopefully, future updates and optimizations will provide a more consistent performance boost across all games.

Tyler

[PrzemekK]

For me reverting Bios on ASRock b450m pro4 from 10.08 to 8.01 helped to fix this issue.