You don't decide whether a console is from one or another generation because of graphics, that would screw up the console generation time-space continuum.
For example, the moment the PSP came out (matching the current gen), the DS would suddenly become a last gen handheld. Meaning all portable systems would go one generation back making the first ever portable generation 0, thus giving an error and making the universe implode.
As others have said, PSX and N64 would be in different generations, effectively making N64 the only 6th generation console and meaning the current HD consoles are the 8th. That would alter the course of history and also send us forward in time to an alternative universe.
No troll is too much for me to handle. I rehabilitate trolls, I train people. I am the Troll Whisperer.
