I wonder if either (a) high frequency trading firms are going to start running their algorithms on iPhones, or (b) Geekbench doesn't accurately reflect the real world performance in some way.

Assuming Geekbench is a good reflection of real world performance (in e.g. games, video encoding, encryption, decompression, compilation, databases, etc), I'm curious to know what AMD and Intel are doing so wrong that a cellphone chip could outpace their desktop chips. I don't think the A20's lithography is vastly better, nor does the chip have more area. Where's the performance difference coming from?

I'd bet (c) the M* variants offer the same generation of CPU in devices like the Mac mini but with more cores, a higher power budget, and less restriction on the code you can run. The A20 Pro just hit Geekbench first, both the A20 Pro and the M6 start shipping this month.

Edit: Looks like a believable M6 result appeared just this morning https://browser.geekbench.com/v7/cpu/354109 ~1.02x single thread & 1.99x multi thread vs the A20 Pro