Aimed one of my GPUs to x13. So far so good with the latest RC2 drivers and sgminer 5 beta showing 2.5 Mh/s.
sgminer --algorithm x13mod --hamsi-expand-big 1 --no-adl -I 18 -g 2 -w 128 --thread-concurrency 8192 -o stratum+tcp://uswest.wafflepool.com:3330 -u XXXXXXXXXXXXXXXXXXX -p d=0.008 -o stratum+tcp://useast.wafflepool.com:3330 -u XXXXXXXXXXXXXXX -p d=0.008