The N97's processor hasn't been confirmed yet. It will be an ARM11 though, according to statements made by some Nokia product team members.

The N95 runs a 332 MHz ARM11, but is dual core (the baseband has its own CPU). The N96 runs a 264 MHz ARM9 and is also dual core. The E71 and 5800 run 369 MHz ARM11s, but are single core.

What all that means is, who knows...