Is this for Nvidia cards only or for AMD?
Those flags are for cuda (nvidia only).
In that chart you can see flags for all cards.
There's one for 2x GTX 580s so messed with that. Originally used an old thread suggesting a 580 profile and it had worked just fine giving me ~130-140MH/sec.
Original was: -gpu=0 (used -gpu=1 for my other 580 to make it work) poclbm VECTORS
New is: -gpu=0 -gpugrid=128 -gputhreads=1024
Now up to ~155MH/sec. Cool
