Alphasim F8-E Crusader

I like this airplane so much I decided to compare FS2002 performance figures with real world specs for the aircraft: it came up short..Real world figures state a maximum attained speed btweeen 1133 MPH at fl350 to to 1322 MPH or 1150 knots between fl350 and 360 ( from another source ). The Alpahsim version is only capable of 709 knots grnd speed or mach 1.25 or so at fl350. This is achieved by a slight dive out of fl410. What happened with the flight model is my question? Also remember, this is on my system: yours might vary. I was simply wondering if anyone else has noticed this anomoly:)Thanks, Sawacs