orbis is rumoured to have 32 ROPs. I was wondering in the context of the 4k talk whether that number was suited to driving that resolution well.
The OP says 8 ROPS for the Orbis GPU, same as last gen and XBox3 is likely the same.
To be honest theoretical pixel fillrates in consoles like 360 and PS3 aren't close to being tapped, what's limiting their fillrate in games is shader performance (the work done on the pixel before its outputted). Probably why they've stayed with 8 ROPS as it'll be ok for 1080p. Having said that 4K isn't going to happen IMO, not because of ROPS (though certainly 8 wouldn't support that) but again because of shader performance (you'd need more shader performance then Sony and MS are providing to process that number of pixels even if you had the fillrate).