I've had this problem, too.
I think I have this resolved over here, using a trick I was using with 2.2.5:
Go to your project's root; make a file called .gitattributes (note, not .gitattributes.txt, just the extension).
Open the file with Notepad++, enter:
Code:
* text=auto
*.fsh text
*.vsh text
*.yyp text
*.yy text
*.gml text
*.png -text
* -text
What this is supposed to do (if I read Git's documentation correctly) is force Git to treat .yyp, .yy, and .gml files as text files, but exclude .png. I
think the * -text excludes sound files (which, strangely, have no file extension). With 2.2.5, this significantly impacted laggy behavior when using Github (especially epic-length wait-times to commit something). I'm really not sure why source-control is still having all these issues in 2.3; I reported a lot of these issues in detail months ago.