As detailed by the good people who make retroarch / libretro –
http://www.libretro.com/index.php/in-the-run-up-to-retroarch-1-1-whats-new-pt-3/
They are working on a better snes core which should work on lower power ARM systems.
Any chance retropie integrates this in the next build?
I find SNES emulation through retropie to be satisfying, but ultimately lacking for the discerning type. Lag, bad sound etc. bSNES obviously not possible but palpably better.