No, the .284 case is not the equal in capacity of the '06 as myth would have it, but it is close and since data for the '06 is usually conservative, starting loads will be plenty safe in your .30-284.
Once you work up to a safe working maximum, say 52-54,000 CUP, you'll have velocities equal or better than an '06 with 48,000 CUP loads, effective barrel lengths being equal.
If your .30/284 is built on a short action, you may have difficulty equaling '06 velocities with heavy or long bullets due to the necessity of deep seating.