Tried the 2.5d and got a lot of stale (but when I switched back to claymore I noticed a lot of stale shares too (15%+)).  When the stale shares went back to normal with claymore 2-4%, I got 2.6b and tried again.  Getting normal amount of stales again, so far so good.

I've noticed that the log file stays at 1 KB until I stop the miner.  Is the log file in memory until I stop it?  I'm worried about running out of memory.