Previous posters pegged it. All depends on where you start.
I believe the mid-point is @ between Greensboro or Burlington on I-40. If you are East of that, 95, if West, 77-26-95.
If you fall in that 'gray' area, I would factor departure time and construction, to avoid RTP/Raleigh or Charlotte at rush hour.
Either way, once you clear NC/SC line, no real traffic bottlenecks til Jacksonville, and that depends alot on time of day.
Drive safe.