The RV620 has a 525MHz core and 400MHz memory. Both cards were tested on a low-end system: Intel Celeron 460(2.4GHz), Foxconn P35A-S, 1GB*2 memory, Windows Vista Ultimate.
The results in 3DMark06:
That's a 35% increase. Not bad but not for hardcore gamers of course.Radeon HD 2400 Pro: 1123 RV620: 1514