What platform is there for PowerPC 970MP? Despite Apple's switch to
Intel, is there going to be a Mac based on this architecture?
My understanding is that yes, Apple will use this chip in their
systems. They are likely to be the last new chips that Apple uses in
their PowerPC based line of Macs.
Are there going to be PowerPC motherboards?
Perhaps a few here and there, but they are likely to be very rare and
very expensive (think $1000+)
Or is this processor dead from a PC perspective?
For the most part, yes. IBM will almost certainly release some blade
servers using this chip (follow-ups to their current JS20 servers).
They may also release some workstations using this processor, though I
haven't heard any announcements for it.
Generally speaking though, other than the Apple systems, this chip is
unlikely to be particularly useable by most average home-users. You
will almost certainly be much better served by an AMD or Intel
dual-core processor instead.