This seems like total bullshit rumor. There is no way Intel found a way to make Gracemont (warmed over Atom) have a higher IPC than Skylake.rip AMD
8 big cores will score around 8250points in cinebench r20 at 5ghz all core, while Zen3 8core 5800x scores 6250 points at 4,8ghz.
Looks like Alder Lake has 27% better IPC than Zen3 in CB r20. 12900k with 8 big and 8 smaller cores will be faster than 16 core Zen3