I ran d.net back on my Mark 1 with Beta 9c, and again now on 2.0 B7. Here are the numbers I got from running it normally:

Mk1 with no player running - ~250kkeys/s
Mk1 with player running ~ 175kkeys/s
Mk2 with no player running ~277kkeys/s
Mk2 with player running (and visuals, not sure about the Mk1 stat) ~ 100kkeys/s

I think the boost in speed from the Mark 1 to the 2 is just the fact that the client has been revised a few times since then.