You're on windows. Do not put intensity above 9 as I have already said. There is a chance you're actually running out of CPU when you enable extra devices. When you change drivers and SDK with cgminer, make sure to delete any .bin files that were generated previously. Pretty much the same combination of drivers and sdk on linux are suitable as on windows. I use the 11.12 drivers that have the 7970 hotfix to get the 7970s working. You cannot run 7970s with SDK 2.5; if it's working with that combination it's only because cgminer has cached the .bin files.