Setting your memory clock higher directly increases the hash rate. Your afterburner settings are not working make sure you are applying the settings before launching the miner.
Download a tool called Hwinfo64.
Install and choose sensors only mode.
Scroll down to your GPU's and look at GPU clock and GPU Memory clock. They should match the settings you have in afterburner, if they don't then you aren't overclocking the card.
Make sure the temp stays between 60-70*C and make sure your GPU Memory errors are either 0 or very low, like 10-20 every minute.
Thanks for the tip on the Hwinfo64. Fun little tool. Is 70*C really the max recommended temp? I have one card that seems to stay at 73 without an extra fan on it, so I put a 120mm case fan perpendicular to it and it is now around 70*C but I am concerned about the summer now that you mention 60-70.
Some articles online say that overclocking the Core Clock helps and some say that only overclocking the memory clock helps. I havent had huge, steady increases from overclocking either, so I will try the Hwinfo along with my MSI Afterburner. Does anyone here have suggestions on how to know how far to increase the clock and remain stable? Do you recommend core clock and memory or just one?