I heard something interesting on the radio today. A Citation X had taken off from St. Paul with a GV taking off right after him. The Citation X, N944QS, was given a climb to FL400 by Minneapolis Center. Center then told him to, "Stop climb at FL260, there is a GV below you that is outclimbing you and overtaking you by 30 knots." The GV was then given an unrestricted climb to FL450. Best I could tell by the radios the Citation was not leveled and was given a progressive climb, but the GV was level at FL450 before the Citation was out of FL390. I know how fast the X is straight and level, so my question is, "Is the Citation X a dog in the climb or what was going on here?"