The thing about empire at war is that it only uses one core, so it doesn't really care about fancy modern PCs. An old computer with one slightly faster core will often run it better than a new one with 8 cores, each individually slightly slower.

All I can suggest is to revert any changes to your settings that you might have made before the petroglyph patch, and maybe try to counteract the lag slightly by reducing your galactic gamespeed by a notch, so it at least runs slightly more smoothly.

You can try the below from the TR forum, not sure if it works as I'm only at week 10 in my new AOTR 190p. campaign i.e. before the lagging issues start getting really bad. Those 10 turns were butter smooth though on the GC map.
As I again have the issue with the !"#¤%&/ freigters not moving I am unsure if I will continue, sadly, worried that the AI is dead/passive, will do a few more rounds and then we'll see...



BadPupper 6 jan @ 5:41
Hey Cory, I might have found something weird with the mod (or maybe the game itself). I've tried every fix/workaround I could find on Google, but running the game through Steam with the mod ID in the settings would only get me 16 fps max with tons of stuttering. However, if I run swfoc.exe and then go into options and select this mod to launch it, I'm able to get 30-60 fps with no stuttering. I don't know why that boosted my performance but I figure I'll leave it here in case other people are having this issue.