After spending time on Apple’s M1/M2 Macs (coming from a large x86_64 desktop), going back to x86_64 feels like a regression, both in performance and battery life.

Isn’t it still the case that, for speeds comparable to an Apple system, x86_64 is still more power/performance efficient than basically any other ARM-based system you can buy?

In raw power x64 is still the king, has always been.

You can skew things by looking only at single core performance (where apples most expensive cpus might win because of their strategy of having fewer but more powerful cores + memory latency gains are much more visible with only one core).

With that said, things are changing in the PC landscape and some extremely powerful and power efficient ARM designs are coming soon. We have already seen a small glimpse of that with MediaTek.

For the most part, yes, which is why he's using a Mac as his daily driver, and ssh'ing into the BSD box