I am not really worried that much about the processor not being up there. It will be far better than what I have, and is smaller (45nm if i saw it right) so cooler, and far over double the power for far less than double the power (34 watts vs 45 watts), so should last about the same on the same battery. (assume for same amount of charge, same RAM, and same video card level).
It should be far better I think at graphics task with 128 sp and DX10 over the 24/8 I have now, well actually 16 (not getting a picture at all on the M90 right now.
and to top it all, the M6400 has windows 2000 drivers! my day has been made. was going to check the other one, the M6600 or M6500 (core series revisions I think) but it took me 25 minutes to get the 6400 up, so I will wait till I am back in the land of ethernet tomorrow to check them.