[V2-V3]

Originally Posted by GeorgeStorm

Just tried setting it up, getting around 50Mhash/s per core of the gpu, and getting quiet a few rejected, about 50/50 atm. Card is at stock, temps are <80 degrees.
Any ideas?

I have a 4870 that runs 90Mhash with a little OC and it uses some command switches or on GUIMiner "Extra Flags" to optimize the Mining client.

The 4870 is not on it yet but will be soon.
You could try playing with adding and removing flags and increasing and decreasing the value
Here are some flags:
-k
phatk
VECTORS
BFI_INT
AGGRESSION=10
worksize=256
FASTLOOP=off