memcached eats up all CPU on Windows with no load

1. Install fresh build on 10.1.5.71
2. Start memcachetest -h 10.1.5.71 -i 50000 -l -t 16
3. Let run for a while
4. Add 10.1.5.72 (also brand new install)
5. Rebalance
6. In general, performance is all over the place
7. After a while, stopped memcachetest altogether. takes a very long time for the persistence write queue to drain. Finally (like 15 minutes later) comes down.
8. now, after another 30 minutes have passed, memcached.exe is still using up 97% of the CPU on the machine, without any load being put against it.

couldn't grab logs out of the UI, but ran browse_logs.bat and the log is sitting in c:\ on the 10.1.5.71 machine...which is also continuing to run @ 90%+ CPU...the 10.1.5.72 machine is using no CPU, by the way.