Lumen GI on Rog Ally broken in UE5 games

[AldoCalrissian]

Hey guys, so I have been tracking this issue for a little while now and decided to make this post to make everyone aware of it.

I started to notice that UE5 titles on the Rog Ally can look really awful when compared to the exact same settings on any other device (including steam deck) .

I Have narrowed it down to the fact that Lumen global illumination just does not appear to work on the Rog Ally in any UE5 game. (driver bug?) I first noticed it in RoboCop: Rogue City, assumed it was just a bug in that game. Then again in Still wakes the deep. And since then I have been checking out as many UE5 games as I can on the ROG. It seems to Happen in every UE5 game on the Ally, with the exception being the few rare games you can disable Lumen GI in the options. Fortnight you can disable it and Silent Hill 2 remake you can enable full hardware ray-tracing for a pretty expensive fix for example.

This bug happens every time and on every Rog Ally, I have compared my experience with YouTube game play videos of the same levels and they all exhibit the same GI bug in videos dating back to the Rog Ally launch (so its not a new bug). I also discovered it affects the Legion Go too. so more a Z1E/780M issue rather than just a Rog Ally issue.

Anyway here are a few screenshot examples of what the bug looks like in action. It mainly affects indoor areas so its visual impact will vary from game to game and level to level. You can really see how drastically this can alter the appearance of game. and as more and more games are coming out now on UE5 I'm guessing more people will start to notice it. I'm already seeing more and more "lighting looks crap in X game on Ally" posts in various places.

hopefully if more people discover and speak out about this bug it can be fixed in a driver update.

Still Wakes the deep Desktop GPU

Still wakes the deep same settings on rog Ally

Robocop Medium Settings desktop

RoboCop Same Settings - Rog Ally

Wukong desktop medium settings

Wukong same settings Rog Ally

[K_Y]

Yes, yes, I encountered the same problem, I hope for a quick resolution, because for silent hill 2, lighting plays a key role.

[Kotern]

I can confirm that this is also an issue on my system. I had an non-extreme ROG before upgrading to the Ally X and both had issues with Unreal Engine game lighting. This will only become more apparent as more games become unreal engine (Like how Halo just announced that it is turning to Unreal Engine 5).

[TristanRW]

Same issue as everyone else. Fix the problem Asus or get Epic to fix it if its an Engine issue!!

[K_Y]

https://www.reddit.com/r/ROGAllyX/comments/1fyz6zc/silent_hill_2_remake_steps_to_enable_shadows/?sha...  - there is a solution for silent hill 2 remake, mabie it will work on other games.

[AldoCalrissian]

Enabling hardware raytracing is not really a solution. Your just replacing lumen GI with a more expensive ray tracing that tanks performance and eats up a lot more vram. Your not really addressing the lumen GI bug doing so just side stepping it. In all UE5 games lumen Gi is the default lighting engine and in most games its the only option. 

[K_Y]

I agree that this is not really a solution, but rather something like a workaround, but I compared and the performance is better than with Rays and FSR3, while there are no glitches, i.e. I am not saying that ASUS and AMD should not solve the problem, I just threw a link, this can give people the opportunity to play if they want right now.

[AldoCalrissian]

Apologies ive seen a few solutions that suggest enabling raytracing as a solution. It appears why this is doing is forcing the game to run in DX11 mode by replacing DLLs  lumen gi is a dx12 feature I believe. Again this is just sidestepping the bug. Would be far better if Asus/amd address the root cause and fix the driver.  

[AldoCalrissian]

I think dx11 usually disables dlss/fs3 frame gen and some other modern bells and whistles. So its a good find in the short term not without drawbacks but your right if rog ally is your only device to play right now this beats the  raytracing "solution"

[K_Y]

In my case - the only device, I am from Ukraine and due to the fact that they are hitting us with energy, I only have portable systems (Nintendo Switch, besides Asus 🙂 )