Well I thought that my main gripe with NIS v21 was just the horrendously poor revised NTB design...
Nope... Shortly after (upgrading?) from NIS v20 to NIS v21 I noticed a steady high CPU resource drag on one of my processor cores. So I popped open Taskmanager and there at the top of the list was a ccsvchost.exe busyly gobbling up both memory and CPU resources...
Hmm... I thought - So I opened the main NIS GUI and took a look at the Performance screen... Oh yes - ccsvchost was very busy eating up all available memory, and using plenty of CPU to do it - I don't think it was doing anything actually worthwhile though. 
So I logged out and back in again (but no restart)... Problem solved...(at least for now)...
Here's a snapshot of the Performance screen after logging back in...
Notice the relationship of the runaway ccsvchost to the v21 installation completion? BTW, I used the NRnR tool to do the v20 to v21 upgrade.