These are the Arch packages built for x86-64-v2, x86-64-v3 and x86-64-v4, which are basically names for different sets of x86-64 extensions. Selecting the highest level supported by your processor should get you most of the way to -march=native, without the hassle of compiling it yourself.
It also enables -O3 and LTO for all packages.
LTO is great, but I have my doubts about -O3 (vs the more conservative -O2).
UPDATE: bah, ALHP repos don't support the nvidia drivers. And I don't want to muck around with setting everything up again.
Another update: I moved to nvidia-open, so now I can try the suggested repos.
Seems to work so far, but nothing 'feels' faster either.
doing this should allow you to use as many optimized packages as possible while still being able to install packages not supported by the alhp