v9.1 is available:
- Improved pool-related routines: less disconnects, more hashrate on some pools.
- Fixed issue with some old 6xxx/5xxx cards ("lowDifficultShare" error).
- Improved pool-related routines: less disconnects, more hashrate on some pools.
- Fixed issue with some old 6xxx/5xxx cards ("lowDifficultShare" error).
Quote
Best "-a" and "-h" values are set automatically for ...290
correct auto "-h" value for 290 is 1280. 
You are correct, 1152 shows 690h/s, 1280 shows 700h/s (Elpida), my mistake, I'll fix it in next update, thanks for pointing it out.