Well, 4.1 (256x16) looks like it should be stable with 1.5625 set. Made it 15 minutes in with 1.55 and it restarted. Not sure how much farther its really feasible to go, at this point I'm going to be happy to hit 4.5 stable, 4.3 looks to be achievable at least. I just saved a validation of 4.1 so I at least have that for you guys. Won't be able to upload it till later though.