My three miners,  a 2.75MH/s, a 900 KH/s  and a 410KH/s have been running solid for about 2 days with 0.77% reject rate.  

This morning I see the reject rate is now all of a sudden pushed over 1%.  I think the current reject rates is much higher with the 512 difficulty.   Don't want to restart to see the real % because I want to see how many days they will go w/o a restart but I just wanted to provide that feedback.