Optimizing UE5: Advanced Rendering, Graphics Performance, and Memory Management | Unreal Fest 2024

As you continue to push the boundaries of the next-gen graphics features of UE5, you may find yourself in unexplored territory with an overloaded backpack and nary a trail marker in sight. How do you find your way back to the trail? Should you be changing how you pack your bag for the trek? Was there anything you could have done before you set out to make things easier? Let’s dive deeper into debugging Nanite, Lumen, and VSM performance issues so that we can get back on to the trail. Then, we’ll learn more about managing the memory of our new graphics features, including how we can leverage virtual texturing to make sure our pack is properly balanced. Along the way we’ll learn about what we can do to make sure we’re staying on track far into the future.

[@mingyenwu9621]

I believe this is the first time I've heard someone in Epic talk about the meaning behind "virtual" in detail. This clarifies things a lot.

[@theQuickRundown]

These recent optimization talks were so needed! Thank you

[@eternalsoma]

Lets say i had this problem yesterday and now this video is here. What a timing

[@Tylru]

Incredible talk. However, if you're going to allow your speaker to continually say the links to all the CVARs will be available at the end... Please make sure the links to all the CVARs IS available at the end.

[@GreenClover0]

There's a linktree link at the end which has links to CVARs for all Mike's presentations including this one

[@blknmild]

Thank you for this video, its EXACTLY what I needed to encourage me to move forward with my indie game project in UE!!!

[@tbvjwodn]

I love how Matt explain things! :) Thank you so much!!!!

Brilliant guy! So informative.

[@dXXPacmanXXb]

Unreal should publish a book with all those console variables and their use. How is anyone keeping track of all of them. Some of them seem so important yet I have never heard about them

[@Unknowable_Void]

Finally a clear explanation for why Lumen might be flickering in certain scenes

[@DanielGoupil]

Great talk as usual thanks Matt

[@pricklyprickle]

Amazing talk i learned a lot from this Epic is amazing at making good informational material

[@d369studios]

Thank you for this video Matt!

[@DannyArtNL]

Absolutely fantastic! Or should I say, ilLumen-ating 😏...

[@zehnjucht]

I learned a lot of new things in here. GREAT talk.

[@51Daedalus]

So how would you actually fix those large yellow surfaces in the lumen scene without pumping the lumen scene detail so much that performance tanks? Sometimes, these yellow parts are closer and larger than smaller stuff behind it that renders just fine into the lumen scene so it can feel incredibly random why its happening.

[@Trait74]

Where are the links? The Console Variables and the Video links? Especially the Lumen Optimization video

[@Cloroqx]

The master returns.

[@yonghengshouhu]

UE5.4.4 Motion Design - Material Designer The problem of multi-layer effect overlay that cannot be saved has not been resolved. . .

[@ChadT-n9q]

I remember the first demo in April of 2020 showing off UE5 for the first time, how detailed and incredible it looked and still looks today, running live on a PS5 dev kit essentially, to now 4 years later and it still seems like everytime they show off scenes like this one they always say "this is not for video games", which is discouraging because wasn't the whole point of these technologies to make games look incredible and now they are struggling to do so 4 years later with a dozen caveats??

[@violentpixelation5486]

❤️💯#gold

[@thhm]

Whats the console command for showing the stat for the virtual texture memory?

[@GES1985]

For packaged actors, is there a way to cull the geometry that is hidden inside of collisions, so that there are no draw calls on the parts of the packaged actors that can not be seen?

[@ciprianstanciu7]

For who's watching, the VRS visualization shown here is broken in 5.4.4. I can't post links here but I posted the fix on the unreal forums. Also with VRS on, virtual textures flicker like crazy, as demonstrated in the video at 14:30 center screen, sadly the speaker doesn't touch on that :/

[@alexandrechekroun]

How do you get the Nanite Variable Shading Rate visualization at 27:29 ?

[@ligazetom]

Could anyone explain 21:00 a bit more? He just dropped it like it's not a big deal having texture dropped when the camera is static. Is there anything to counter that or thats just it. Is it every 16th pixel on screen? So if my texture takes more screen space it's less likely to be dropped?

[@Gundir_Cap]

where can I get a link with commands and their description? I think it was said that it will be under the video

[@ergin3d]

So Matt is doing the math... :P

[@mindped]

so how come when i disable reverse index buffer... i can still scale meshes in negative just fine?

[@mindped]

Anyone find that link with all the cvars that he keeps saying is included with this video? (but is not)

[@Horizontff]

Esta equivocado en el video. El simple hecho de usar nanite supone un costo. Si usas nanite para mallas con pocos poligonos etc el costo de activar nanite es mayor al coste de la malla por lo que es mejor no usar nanite para este tipo de mallas para tener mejor rendimiento. Estaría bien que mejorarais la optimización de lumen, Ray tracing, Virtual shadow maps, AO

[@D3kryption]

I'm curious to hear about the latest nanite videos and how people are saying its highly bad for performance and people should stop using it. It'd be good to here from Epics side :D

[@GlassesAndCoffeeMugs]

Tbh the fundamental problem with Nanite has always been "it works best with super high poly geometry and all the other expensive modern features" and even then it doesn't always work better than LODs. So the issue is you're already starting the race 4 laps behind so to speak in terms of performance, since you're limiting yourself to mostly super high poly geometry which is heavy to begin with regardless of Nanite, and also forcing yourself to use the most expensive graphical features. But to be fair he does mention this in the beginning of the video, he's demoing arch viz stuff, high poly models, and explicitly says he is NOT talking about realtime games.

[@D3kryption]

@@GlassesAndCoffeeMugs Hey! Thanks for the reply. That was my basic understanding of it, but I just figured it was the whole "you don't need LODs anymore" and it was just a HUGEEEE time saver. But now more and more videos are coming out saying how bad it is for games. By the sounds of it, its kinda the same with lighting. If you baked it (or create lods) its always going to be faster predefined than in real time lighting (or nanite)

[@ptcmia]

@@GlassesAndCoffeeMugs do you have an example of a scene with LOD running faster than the same scene in nanite?

[@redtroll80]

@@ptcmia kzbin.info/www/bejne/embdnHqenLCKh6s LODs are probably always faster, but for me as I was doing my first game, nanite was huge time saver...just import high res mesh, no lowres mesh needed to be build...

[@d.w.s.4320]

Nanite was probably the largest jump in modern gaming graphics. Saying it is bad for performance is just nuts.

[@hellomistershifty]

Using SVTs? Great. Disabling static lighting if you're using Lumen? Awesome. Doing both of those things? Full crash with Assertion failed: !UE::RenderCommandPipe::IsReplaying() whenever you edit a material with SVTs Why is the fix for this error, UE-219361, slated for 5.5 and not in the 5.4 bugfixes?

[@FergusonGary-m8k]

Quincy Dale

[@IstyManame]

"If it can be nanite it should be nanite" That is a lie, if you use nanite for meshes with small amounts of polygons the base cost will be way higher than the performance gains

[@Dante1243]

💯

[@drinkwwwaterrr]

Nanite is entirely impractical unless all your meshes are unoptimized in the first place. Having well managed LODs gives you MUCH better performance while still looking great.

[@e-frame5344]

Youre only right about this if you dont put this into context to all other elements the engine offers like Virtual Shadowmaps and Lumen :3

[@jackryan8588]

@@e-frame5344Unless your making an open world game with photoscanned and film ready assets, it’s a waste of your time and performance.

[@Smokey-A]

@@e-frame5344 Lumen and VSM's have their own issues too.

[@RogueBeatsARG]

Wait, so enabling DLSS and FSR is not Optimizing a game? damn need to tell 90% of UE5 game devs before they release

[@th-redattack]

😂

[@angelinajeffree7768]

Thomas Frank Taylor Carol Jones Christopher

[@BaconSebastiane-s8x]

Lewis Joseph Brown Charles Jones Betty

[@qu3xHG]

I like that even on official learning videos kzbin.info/www/bejne/mpuXnIGkn5l5d7M you can kinda see the draw backs of modern graphics models were content starts to flicker at far distance. Also when you hear the buzz words in 16ms window you can make your conclusion that UE only cares for a 60fps target rather then ultra high frame rates

[@senhor6863]

The flickering back there is actually just lumen, those objects are so far away, and their pixel size is so small that Lumen just shits itself, if you wanna keep everything stable, at high quality and performant, you should probably put a distance limit of Lumen, whether that's a fair trade its up to you, but they definitively don't talk about that

[@MoTHO_BRO_293]

Hi

[@gofromielx]

I find all these videos funny: "you just have to check this box"... and yet all UE5 titles sutter like hell.

[@AkitaMix]

Extraordinary claim

[@Mr4Goosey]

That checkbox is a recent addition. Most UE5 titles that have recently released have been 5.0 or 5.1 titles, and this problem had not yet been solved in those releases.

[@SyntaxDomain]

​@@Mr4Goosey Which checkbox specifically?

[@LittleBlue42]

Mostly fixed now in recent versions. Lots of new updates to the back end.

[@shannenmr]

Stuttering is usually due to compiling shaders which until recently was solely the responsibility of the Developers to do offline (PSOs) and include in the package, many Developers either didn't do this or usually do a bad job of it (it requires playing/moving through every level fully while running the process). In the recent versions of UE5 they have made strides to pre-compile them while map loading and asynchronously while you play the game plus displaying a default texture if required instead of blocking the thread (stutter) while it compiles it but there is still some improvements to be made.