Possible fix for Lag with mod lights on AMD GPUs

[Duftmand]

I think a steam user might have found the solution to the severe lag you get from having vehicles with their emergency lights on (especially bad with modded american vehicles with lots of lights) and some AMD cards, at least mine and a few others.

i recently got an AMD 5700XT, swapping over  from a decent Nvidia card, and my framerates have gone through the floor. Just now i found a post on Steam Discussions on the EM4 Deluxe version explaining that changing a string of code in the Em4 cfg file solved their problems.

Simply change 

<var name="e4_mbfastcopy" value="1" />

to this

<var name="e4_mbfastcopy" value="0" />

ALL CREDIT goes to BetterWarrior and his friend for solving this issue, the original post is linked below, if you want to go thank him if it works for you.

https://steamcommunity.com/app/757210/discussions/0/2935742047961399361/

I just tested with the Harbor City mod, 12 fire engines all with their lights on, and my game held around 25-30 frames. before applying the fix i would get around 10 with just one engine on screen.

If anyone knows what the snippet of code does actually do in-game, i'd curious to know.

[itchboy]

This solution was shared to me a few months back and I got no improvement from it, however I was on an Nvidia GT430 at the time. Now I'm on a 1050Ti and I still get no difference, so it seems to be something unique to AMD cards. I never thought of this before.

I will be pinning this thread so that other AMD users can see this and try it out. It might be placebo, it might be real.

Until we figure out what fastcopy does, only then we can isolate what "task" is making Em4 slow down. A 5700XT absolutely should have no problems running Em4 at 100+ FPS, even on a mid range CPU.

[Duftmand]

22 hours ago, itchboy said:

I will be pinning this thread so that other AMD users can see this and try it out. It might be placebo, it might be real.

Until we figure out what fastcopy does, only then we can isolate what "task" is making Em4 slow down. A 5700XT absolutely should have no problems running Em4 at 100+ FPS, even on a mid range CPU.

It does seem like it only affects AMD cards. Maybe i should try it out on my laptop (Nvidia GTX 850M) and see if it does anything, though i suspect the bottleneck on that system is the CPU. On my desktop with the 5700XT i run a i7 4790K at 4GHz, so in theory it should run a lot better than it does.

There were supposedly some other fixes for users of Nvidia hardware but i am sure you've tried most of those. 

If you need me to change the post title to something more concise, just let me know and i'd be happy to! 

[itchboy]

I tested Em4 on my father's laptop which had a 920M...no problems except heating.

According to other forums, NVIDIA hardware like high end 1070s and up and 16-20 series cards have the same problem as the AMD ones. It remains to be seen if the 30 series suffers the same issue. Hopefully somebody can share on that. It seems to be some kind of new tech implemented into these cards that makes Em4 run terribly on them.

Back in the old days of 2007, I ran Em4 using an ATI Radeon 9200, and it was perfect other than massive lag when shadows were turned on. Things were simpler back then.

[Duftmand]

It seems like the easiest solution to this is to try to find a second-hand "old" high-end graphics card from the time before the game started to have issues, and use it as a sort of secondary card. Maybe Emergency is unable to make use of the resources available with newer cards. That doesn't seem easily fixable though. I really hope EM5 gets more people modding it so it can have the same lifespan as Em4

 

[itchboy]

We'll have to ask around for who owns what and who can test.

Since 2008 we already knew Em4 can't use more than one core CPU wise. GPU wise, we thought there was a "hard limit" on how much VRAM it could use and any more than that would just be nothing to the game.

The AMD slowdowns were a further escalation because it went from "Em4 can't use these resources" to "Em4's graphic function calls make new hardware slow down". The problem isn't just unlocking the game memory, but rather the instructions for rendering graphics on that old game engine are no longer compatible with modern tech.

The game hit the end of its shelf life in 2015 tbh. The only thing keeping it going is that NVIDIA users can play the game. This won't last very long after 2020.

Blame the devs, they should have at least created patches to make the game treat new hardware as if it was the original supported cards.

[Duftmand]

I doubt that Sixteen Tons Entertainment would be bothered to fix it now. Has anyone had contact to the devs of EM4?

[More Than]

Glad to see that i've helped someone although i have heard from someone in the german forums that it slow down the modloading? Not sure about this since it's untested.