You can overclock past 920 with MSI Afterburner (or whatever the limit is you currently see). All you need to do is "unlock" MSI Afterburner to allow for overclocking/underclock past the predetermined limits.

- Go to the folder where Afterburner is installed. For Win7, I believe it's /Program Files (x86)/MSI Afterburner
- Find the .CFG file and edit it with notepad or other text editor
- Scroll to the bottom and find: "UnofficialOverclockingEULA ="
- Change to (without quotations, no period at end of sentence): "UnofficialOverclockingEULA = I confirm that I am aware of unofficial overclocking limitations and fully understand that MSI will not provide me any support on it"
- Find: "UnofficialOverclockingMode = 0"
- Change to (without quotations): "UnofficialOverclockingMode = 1"
- Save .CFG file and close
- Restart Afterburner and you should now be able to change core and memory clock higher or lower than before.