4.10 -> 4.16 Big performance issue

Hello everyone,

Today I started to play a little with foliage and dynamic lighting in UE4.16. And I noticed that my fps drastically fall down.
I remembered that it worked better when I previously tried to do something.

I’ve asked our Designer to create a quick comparison.
And guess what? There is a big difference in performance between those two versions 4.10 and 4.16.

4.16:
6aa397441980e7adfa233e2680985e7661935ae2.jpeg

4.10:


In both cases, the scalability settings are the same. Only one directional lighting. Maps are the same. And you see the difference in fps. Missing 5ms, just by switching UE4 version.
I know that 4.10 was just after the big show about Open World, Kite Demo, Mountain Landscape - all aspects of the environment were great.
I’m sure that by developing an engine for over a year you made it even better in each aspect. And I assumed that rendering performance should be improved as well or at least don’t go down.

Can you say what changed? And more important how to get back missing 5ms?

I’m asking because I’ve started a new project in 4.16 and I’m not sure if I should continue it in this version if there is so big performance gap.

Hi,

I am also interested to have a explanation …

This is very intersting as we were planning to migrate to 4.16 ourselves. Looks like we’re going to wait till the first hotfix.

May be related to this: Trying to Understand Kite Demo Performance Implications - Rendering - Unreal Engine Forums

TL; DR: LOD settings will be broken if upgraded from version lower than 4.14/4.15.

In your scene there are a lot of trees, which is the typical problematic scenario.

I’ve checked this and looks like it is not related to LOD. In both versions, LOD settings are the same to the level of billboards.
But I found info in this topic that UE4 is just ****ed up if it goes for foliage.

Yes, there are few trees in the scene. Look on the kite demo - you will see what it is a ‘lot’. About Kite Demo, in version 4.9 it worked for me on 35-40fps without a problem. Now it is almost not working - 5FPS is a joke.

Go to the wireframe view and see if they are the same. Is it the lighting or is it something else?

I’ve checked on the wireframe and both are the same. On unlit mode, both scenes have 120 FPS, so it can be a lighting problem.

How about polycount? STAT RHI

Maybe you should show the whole Stat report instead of FPS only for 4.10 so you can see what’s the difference

It is about 7,5M. I’ve added screenshots with polycount.

What kind of Stat report would you like for 4.10? For 4.16 I just used stat GPU, this option is not present in 4.10 :frowning: