As mentioned by someone else, south of Atl in the Henry County/McDonough area is now just as bad as downtown. I suggest studying the route on Google Maps and make note of which lanes you need to be in and then just stick to them. Don't try to do a bunch of lane changing thinking it will get you ahead.
On the north side of the "connector" (where I75 and I85 run together), I75 splits from the right lanes and they cross each other after the split.
Also, they've now painted large interstate "signs" on the lanes. They help a lot.