*looks into crystal ball* a bit over 1Gh/s at a bit over 250W with memory underclocked, ~300W at stock mem clock.
Bump core voltage to 7970 levels, memory to min clock, core clock to well >1.1GHz and you're probably looking at >1.3Gh/s at ~400W.
Compared to $299 5970s it obviously loses massively for price/perf, but supplies of those are drying up.
Compared to $699 6990s, even at $899 it looks like a clear winner; higher density, higher efficiency, better price/perf.
And likely far greater % of retained resale value.