Maybe PS3 with only 256mb of XDR ram with bandwith of 60 Gb/s, and a RSX that lived up to its hype?
Would have a PS3 with potent RSX and 256mb of super fast XDR ram hold its own against a 512mb 360?
The 360 offered 8 times the RAM of its predecessor.
The most popular PC RAM configuration in 2006 per Steam was 512MB.
Orbis should offer 8 times the RAM of 360.
The most popular RAM configuration today per Steam is 4GB.
Don't know if I'd characterise Orbis as having 2013's '256MB' of RAM. It sounds more like MS is going above and beyond on that front rather than Orbis underdelivering.
If you really want to draw an analogy with the prior generation, both Orbis and Durango sound a lot more like 360 than either does to PS3.
Orbis sounds like a next-gen 360 that and substitutes main memory bandwidth for eDRAM.
Durango sounds like a next-gen 360 with a less powerful GPU and more RAM.
But historical analogies, as simplistically appealing as they can be, can also be very misleading so...