are you comparing the same models? How did you calculate the TOPS for M3 Ultra?
An M3 Ultra is two M3 Max chips connected via fabric, so physics.
Did not mean to shit on anyone's parade, but it's a trap for novices, with the caveat that you reportedly can't buy a GB10 until "May 2025" and the expectation that it will be severely supply constrained. For some (overfunded startups running on AI monkey code? Youtube Influencers?), that timing is an unacceptable risk, so I do expect these things to fly off the shelves and then hit eBay this Summer.
Downvote away Cupetino Tea drinkers!