I use a Lenovo Y50-70 with the following specs:
OS: Win 10 (Build 10586)
CPU: i7-4710HQ @ 2.5GHz
RAM: 8GB
GPU: GeForce GTX860M w/ 2GB GDDR5
HDD: 500GB
With that aside:
Before upgrading to Windows 10, I could consistently get about 40FPS (not to mention it felt buttery smooth) playing on High. Now that I've upgraded to windows 10, I'm barely pulling 30FPS, but the difference is VERY noticeable: watching the AT-STs and AT-ATs move looks like stop motion, the Hero/Villain cutscenes are choppy as heck, and flying is almost impossible.
Worth pointing out that every other game on my computer runs perfectly fine with the exception (of course) of Battlefront.
I was reading through some suggestions on this thread and saw the idea to check to see if my Intel 4600 graphics driver needed updating. Sure enough, it did. I restarted my computer and launched Battlefront and it played perfectly. I closed it for a couple of hours and then played it again and now it's back to the crappy 28-30FPS performance.
Let me knock these ideas off your checklist before you suggest them:
-GTX860M driver is up to date
-played with nothing open on my computer but Battlefront
-restarted the game and my computer multiple times
-turning graphics down to "low" doesn't help
-disabling my Intel driver when I launch the game gives me this message
-Battlefront is using the 860M and not the Intel 4600
As everything else works perfectly fine on my computer, I refuse to revert back to 8.1 just because this game does not work like it should.
I have tried all of the above suggestions and uninstalled GeForce experience and I am still barely getting (very choppy) 30FPS.