Your overclock is too high, memory is messed up, or thread_concurrency is too low (but it shouldn't be).
For some reason too if I use cgminer to mine with I get invalids for my 69xx cards, but if I use reaper it's fine.  No clue why this is.

Also enabling stratum will reduce stales but not invalids.

Also your GUI is way larger than mine, I'll have to figure out why that is (it's supposed to be smaller by default).