Down to 48 vsel with 1.15ghz. Survived a SetCPU stress test for several minutes. I'll keep trying lower voltages. Looking good though.
# cat mpu_opps
mpu_opps[4] rate=1150000000 opp_id=4 vsel=48
mpu_opps[3] rate=800000000 opp_id=3 vsel=57
mpu_opps[2] rate=600000000 opp_id=2 vsel=44
mpu_opps[1] rate=300000000 opp_id=1 vsel=32
# cat mpu_opps
mpu_opps[4] rate=1150000000 opp_id=4 vsel=48
mpu_opps[3] rate=800000000 opp_id=3 vsel=57
mpu_opps[2] rate=600000000 opp_id=2 vsel=44
mpu_opps[1] rate=300000000 opp_id=1 vsel=32