Only the 1080ti work better as I could increase the PL. The 1070s are still hanging everything and they are at max PL -- I already tried stock settings. Gminer is definitely doing something better than miniZ given the problem doesn't exist and it also hashes faster. I met this problem on quite a few miners (even Gminer at first, he fixed it in the meantime) ... it's always because of inefficient use of CUDA calls which end up hogging the driver unnecessarily, being amplified by the number of GPUs.

At 5 GPUs you're mostly going to be ok. 7+ and you need to be increasingly careful.

I only used miniZ on 150,5 because Gminer's devfee pools choked and killed mining (so in that regard you've already beaten Gminer )