don't know why you are replying to me with a quote I didn't make. I never claimed 400. I just illustrated the concept of out of order execution.
Yes I know, that is why I wrote "everbody" at the beginning. My apologies.
P4 is 128 GPRs (integer), right?
It has 128 physical registers to hold the GPRs. That would mean 128 - 8 or 120 rename registers. So a P4 can have up to 120 integer operations in flight (not yet committed) at any given time.