Just got my batch 2 Mini yesterday.  Ran it at 650 Mhz all night and had no HW errors and minimal pool rejects (using nanopool).  Getting around 14.8Ksol/s.  What's odd is I changed the cgminer.conf to set the speed to something higher but anything higher than 650 just gives me a really low hash rate, around 4.5Ksol/s, even 655 Mhz.  No HW errors, just slow hashing.  Anyone else experience this?