M1 Max has a die-to-die interconnect, which lets Apple link two of them to create the Ultra, giving it basically double servings of everything -- processor and GPU cores and so on. It uses high-bandwidth memory and supports up to 128GB, but combined it takes less power than two separate chips.
The chip debuts in the new Mac Studio, a computer that looks like a double-height Mac Mini, though the base configuration comes with the M1 Max. Apple has positioned its performance as equal to or better than the Mac Pro, making it what sounds like a great option for the bulk of creators who really don't need the expandability of the Mac Pro.
The new Mac Studio is full of venting and a big cooling system, has six Thunderbolt 4 ports and can drive up to four Pro XDR monitors. It'll cost you $1,999 (£1,999, AU$2,499) to start or $3,999 (£3,999, AU$6,099) for the version with Apple's new M1 Ultra chip. You can order it today and it ships starting March 18.
Apple also hinted that there's a Mac Pro upgrade coming, "but that's for another day."