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]

Hello, I tried to reply to your post in the topic, but for some reason after refreshing the page I don't see my reply, I decided to reply in a private message, please see the private message from me.

[AldoCalrissian]

Hi. Im trying to DM you but wont let me keeps telling me I have reached the maximum amount of DMs allowed.

How else can I get you this information?  

[K_Y]

I wrote in a private message all the information that Anbby_ROG requested, here I also did not succeed, the message seems to be left, and then I refresh the page and it is gone.

[Anbby_ROG]

Hi @K_Y @AldoCalrissian ,

Thank you for providing the information. 

I will forward it to the internal team for further analysis and confirmation. I will keep you updated with any new information as soon as possible. Thank you!

[K_Y]

bazzite - On one of the forums I was told that it will work well on this operating system, but I have not yet done such testing.

[Legionkin]

no thanks, i prefer a OS i can use instead of troubleshoot the moment the dev makes a mistake or stops support.

[ia4]

Yes I can confirm this issue with the ROG Ally. You can also add "The Casting Of Frank Stone" To the list. I think the UE Lumen is broken in general and it seems to me it is a hardware issue.

The issue is much severe that it currently appears, mainly because it impacts almost all major UE 5 game releases on all rog Ally hardware. E.g. Silent Hill is completely broken because the entire gameplay is based on lighting/darkness.

The lumen layer is not being processed and simply ignored by the Z1 extreme. The result is complete absence of shadows and lighting. If you buy a silent hill game and Ally is your only device (like me) then you are stuck with a broken game. However I would like to add that in silent hill, very rarely there are situations when the lighting works (with ray tracing off of course) but without the ability to debug I cannot say why and how. Needless to say,  Asus or AMD will have to fix this issue. I am sure internally AMD (at least) have be aware of it.

[AldoCalrissian]

Someone has figured out the issue and made a mod as a temp fix.

https://github.com/alxn1/d3d12-proxy/

Appears UE5 disables lumen Gi when it detects 0 dedicated GPU memory. This mod spoofs your amount of Vram so lumen is enabled again.  

Hopefully AMD/Epic can find a more permanent official fix now the cause of the issue has been discovered. 

[ia4]

THANK YOU! This is an excellent find. I tested it out on still wakes the deep & The silent Hill and it works! For anyone interested, the Device ID that needs to be changed in the .ini file for Z1 Extreme is, 0x15BF. The Vendor ID remains the same (0x1002)

This brings me to another issue about this device which I did not bring up earlier. It is the VRAM allocation table. For most games it is completely broken. For e.g. (If I remember right) for call of duty if I assign 8gb VRAM, the game only reads 2GB for some reason, the in game bar shows over flowing of VRAM and vice versa. The "Auto" is never accurate as well. After extensive testing I found 6GB to be the sweet spot but this is also just a work around as most games never show actual 6GB for some reason. The value they indicate is completely off. The Last of Us part 1 is another good example.

[Anbby_ROG]

Hi All, 

After verification AMD, the Lumen GI effects in UE5 are not optimized for iGPU, resulting in the loss of lighting effects when playing with the iGPU. ​
Since this issue cannot be optimized through AMD drivers. We have already reported this issue to Epic and recommend that users experiencing this problem provide feedback to the developers as well. Thank you for your understanding.