First off, "up to" is the most bullshit metric. I am also up to 10x more productive when I get coffee, but that's when comparing to days where I just play Satisfactory all day long.
Secondly, "compared to a random HP AIO PC with a 5 year old CPU" (since there are approximately zero chances that the most popular PC in a market that is heavily Apple dominated would be a 2023 Raptor Lake) is just, once again, Apple's piss poor comparisons.
Yes that's because they don't price match.
If they would, the Apple computer would still some better things about it but it wouldn't win a lot of benchmarks, if any...
FTA: "Compared to the most popular 24-inch all-in-one PC with the latest Intel Core 7 processor, the new iMac is up to 4.5x faster.1"