Thanks for the reply. We are currently working with a Microsoft Tech support person and have tried a variety of things. Some had no effect, however setting the CoordinatorQueryMaxThreads =2 did help the CPU utilization stay around 25-30%, but, then queries by the useres were vastly slower. According the the tech person:
When the concurrency is set to 6 partitions with your original memory setting, SSAS alone can use up to 11*100% CPUs. Each partition processing job can create multiple threads. So 12 core may not be enough.
(As a side note, we have 32GB RAM) RAM doesn't seem to be the problem though(yet), since the CPUs max out within 15-30 seconds of starting the processing, and there is plenty of memory for at least 10 minutes based on PLE and other counters.
I will have to try the ThreadPool\Process\MaxThreads and MinThreads settings, since apparenty we are not using Lazy Processing.
Developer is out...so I'll get back in a couple days.