I'm glad the miner works for you, hopefully I'll get paid for the bounty soon. For everyone playing with command line options here are the settings I use for R9 290: -I 18 -g 4 -w 128. I have not tested it on NVidia yet, will do that today, but do not expect wonders. If there are any serious bugs you can report them on eduffield's github.

Expressions of gratitude for the miner shall go this way: XjzvkWNMu5MNk1gNVykJ6CK1u3pAm47oha