[Symmetry]

They don't require more transistors, they require bigger transistors. Ideally if transistor A is pushing a line with twice the capacitance attached compared to transistor B, transistor A would be twice as wide and so have twice the drive current of transistor B. But of course making transistors bigger increases the capacitive load of driving them[1]. So you solve for an equilibrium trading off the current to capacitance ratio against total chip size. And the Ryzen 4 versus 4c choose different ratios to optimize.

[1] Back in the day due to the intrinsic capacitance of the transistors themselves. These days more because bigger transistors are further apart leading to more line capacitance.

[ComputerGuru]

Is none of it based off of binning now, with sections of lower-performing chiplets or cores fused off to make the efficiency cores?

[wtallis]

It is very rare to be able to fuse off part of a CPU core. Fusing off part of its cache is common, but other than that the only example that comes to mind is some server CPUs where Intel fused off the third vector unit.

[ComputerGuru]

Oh, right, this is part of a core not a whole core. AMD often fuses those off for lower part number SKUs.

FWIW Intel supposedly “fused off” avx-512 in alder lake though I don’t think that was what was actually done, physically speaking.

[wmf]

No, binning can't make cores physically smaller which is what AMD is doing.