[Bug Report] Massive performance issues in UE4.8.1 (incl. documentation)

KAEPS133 · July 9, 2015, 2:10pm

Hi everyone,

since I’ve updated from UE 4.7.6 to 4.8.1 I have massive performance problems. Maps that worked with constant 120 FPS are now running hardly with 20 FPS. Since I wasn’t able to find any solution and just some awnswers from Epic staff “Until now we weren’t able to reproduce this problem” here is what I found …

My system:
CPU: Intel Xeon E3-1231 v3
GPU: Sapphire Radeon R9 290 Tri-X OC (4GB)
RAM: 16 GB
OS: Win7 (64Bit)
UE: 4.8.1

All maps are running with full dynamic lights and all props are low poly.

[1]
http://fs2.directupload.net/images/150709/temp/g7dtx2na.png
This is a new map that I started in UE 4.8.1, It only contains a medium sized landscape and some lowpoly buildings. If I look in this direction everything is fine …

[2]
http://fs2.directupload.net/images/150709/temp/mp5vowji.png
If I turn a bit to the left the FPS drop by 40 FPS.

[3]
http://fs1.directupload.net/images/150709/temp/afpfhxkq.png
Switching to Wireframe or Unlit fixes the FPS back to 120.

[4]
http://fs1.directupload.net/images/150709/temp/astlbcja.png
The use RAM and VRAM is this Map is not quiet high even if the FPS are dropping down to 80.

[5]
http://fs1.directupload.net/images/150709/temp/m46b7k9a.png
If I load a Map i started making in UE 4.4 and alwasy converted to a newer version the required RAM explodes. It should use a bit more RAM because it’s already a detailed map.

[6]
http://fs2.directupload.net/images/150709/temp/gcntx22l.png
The Map is loaded and almost nothing is visible and the FPS drop instantly to ~45 FPS

[7]
http://fs2.directupload.net/images/150709/temp/9b52sjmh.png
Switching to Wireframe/Unlit doubles the FPS

[8]
http://fs2.directupload.net/images/150709/temp/q8zvq67c.jpg
If I walk around the corner and a bigger part of the Map is visible the FPS drop to ~20FPS

But now comes the interessting part. If I turn down the shadow quality to low everything is runing fine with constant 120 FPS. If I set shadow quality to medium, high or epic the FPS are always down at 45/20 FPS.
So I think there is a massiv problem with (dynamic shadows) in the current version.

Has someone found any other solution for this. This is a very big problem for me right now because I planned to prepare the announcement and a Kickstarter campagne with gameplay trailers and it’s not possible in the current version.
I would be pleased if there could be a a fix for this in the next days.

Best,

Hevedy · July 9, 2015, 2:25pm

You are using the default light without DFAO or things like that no ?
And the shadows draw distance is the default distance or no ?
*For dark shadows you need to use a secondary light or a skylight.

KAEPS133 · July 9, 2015, 2:36pm

I’m using the default light without DFAO, shadow draw distance is default and I already using a skylight.
It’s the exact same setup as in 4.6.7 were I was able to play it with 120 FPS.

anonymous_user_fd738307 · July 9, 2015, 3:44pm

Eh, shadow performance is pretty substandard, even though they are good looking.

You should try to add in DFRSS (distance field raytraced soft shadows) for longer distances and tweak your CSS cascades a lot. That should give you a boost in performance but don’t expect to get your 40fps back, more like 10.

KAEPS133 · July 9, 2015, 4:19pm

Alright but why was it working in 4.7.6 with 120FPS and with the new version it’s unplayable?

anonymous_user_fd738307 · July 9, 2015, 5:15pm

ah that i don’t know.
Everything changes from one version to the other. Maybe they are working on something experimental and left bits in there that kill performance.
I guess we’ll never know until we compare the sources, which is frankly too much hassle if you’re not an Epic employee or an AAA game studio employee that needs to fix things fast.

Let’s wait for an official explanation.

jonimake · July 9, 2015, 5:37pm

Since it’s your GPU that’s taking too long per frame, I suggest you show us what the GPU profiler says: GPU Profiling | Unreal Engine Documentation

KAEPS133 · July 9, 2015, 9:56pm

Thank you jonimake!
I checked with the GPU profiler and noticed some problems with my Blueprint light sources.
2-3ms for the DirectionalLight is ok in my opinion for a entire map. But why are my office lamp blueprints forcing so much problems now? I removed all of them and I’m back at 100-120 FPS but now all my switchable lights are missing.
Any idea how to solve the problem with this lights? They are pretty much important for the game. Is there a way to cull blueprints over distance ? It’s very strange that I have these problems now in 4.8.1 and not in older versions. There must be something wrong …

http://fs2.directupload.net/images/150709/temp/mmidkju2.png

anonymous_user_a08c0bf2 · July 14, 2015, 7:28pm

Hey KAEPS133,

Thanks for providing as much information as you have. I have ran through the differences of the GPU process when lights are on and off within a level. I did not notice a huge difference between the lights tested. Could you please provide us with your blueprint set up for the light so that this can be tested further for possible bug reporting?

Thanks!

KAEPS133 · July 15, 2015, 1:50pm

Hey,

tested it with 4.8.2 and no change. It even doesn’t matter if I add a Blueprint light or just a default point light and set it to movable. The frame drop is the same.
[video]- YouTube

The added light is the only light source besides the directional light.

anonymous_user_a08c0bf2 · July 15, 2015, 2:26pm

I would highly suggest that you submit an AnswerHub post for further assistance. I have yet to be able to replicate this issue by using ‘Stat FPS’ or ‘ProfileGPU’. When you submit your post to AnswerHub, I would highly suggest that you provide at least the screenshots of your blueprints being used in order for us to replicate.

Thanks!

KAEPS133 · July 15, 2015, 2:34pm

I’ ve already submitted it to the hub.

I’ll update this thread and the Hub as soon as I’m back on my PC.

KAEPS133 · July 15, 2015, 3:22pm

So here are some screens:

This is the Blueprint from the video. Just a normal pointlight, nothing special.

This is just a dragged in point light that is set to movable.

Both of them have the same result as in the video above.

I hope this can help you to find the problem.

Stephen_Ellis · July 15, 2015, 5:53pm

Thanks for providing this information. We will continue to investigate this report on the AnswerHub post: Updated from 4.7 to 4.8.2 -> massive performance issues - Debugging, Optimization, & Profiling - Unreal Engine Forums

Please be sure to check there for updated information.

anonymous_user_39dfe35e · July 15, 2015, 6:07pm

point lights (movable) did not make any trouble in my project going from 4.7.4 to 4.8.1.

If you replace the wall material, or any other material with light interaction from this point light, by the UE4 default material, then is it still like this?