Q: What should my Work Utility (WU) be?
A: Work utility is the product of hashrate * luck and only stabilises over a
very long period of time. Assuming all your work is valid work, bitcoin mining
should produce a work utility of approximately 1 per 71.6MH. This means at
5GH you should have a WU of 5000 / 71.6 or ~ 69. You cannot make your machine
do "better WU" than this - it is luck related. However you can make it much
worse if your machine produces a lot of hardware errors producing invalid work.
http://ck.kolivas.org/apps/cgminer/READMEThat's taken from the Bitcoin mining readme; scrypt, you're aiming for 0.9 of your hashrate.