Well, arguably, SGI didn't innovate in CPUs - that was MIPS which they bought and then sold again. No, their real innovation was in graphics and system architecture, IMO.
Correct. Specifically, they were phenomenal in terms of their "backplane." ccNUMA, later NUMAFlex was an incredibly scalable way to communicate between nodes and is how they scaled Origin and Altix. Crazy scalable.
After a number of decimal places, nobody gives a damn.