Roy Jones would get knocked out but it has nothing to do with flaws in Jones' style. Tyson would put him on the ropes, and that would be it.
This would be Roy's last ever fight so he would deserve a massive payday to cover the medical bills after a very brutal first round K.O.
Jones can pull a Holyfield on the tyson of the late 90s. Holy doesn't have much power either. Prime Tyson will kill him though.
If Roy had fought Tyson after Ruiz, in 2003, he might have won, Tyson was pretty much shot by then, I think it was the year Danny beat Tyson. But Roy would have no chance against Tyson before the Lennox fight.
Are we talking about the proposed '03 fight after RJJ beat Ruiz? Because I really hope you're not asking prime-for-prime here.
If you answer the question whether Tyson hit harder and is faster than Tarver or Johnson then you will find immediate answer.