The title is quite self-explanatory, really.

I use cgminer on Ubuntu 12.10 to mine bitcoins in the 50BTC pool. I have three workers set up. If I run multiple instances of cgminer, each targeted at their respective workers (1, 2, and 3), would this increase profits or just waste power?

I notice this because cgminer only uses about 80-90% of my GPU (6570) anyway. Thanks.