I just ran the utility
here on a laptop with a Ryzen 7 2700U and it looks like AMD
Zen indeed uses 66-bit pi, because the output of
fpuaccuracy examples
for the "sin near pi" case is the same as the example output supplied with the program, which was run on an Intel Core i7-2600 (
Sandy Bridge). I'm presently away from my
Zen 2-based desktop (Ryzen 9 3950X) but will test it when I get a chance. I doubt the result is going to be any different, though. —
bwDraco 5 mins ago