System load jumps to 400+

[Mitch Granger]

I've got an out of the box ActiveMQ(5.2.0) setup that's doing about 
500,000 messages per queue on 3 queues via the stomp framework.

After a while(hours/days) I get a flood of "Memory usage change.  from: 
99, to: 100" messages in the log and then it just loops on restarting 
the transport followed by the system load jumping to 400+ and no more 
response.

Has anyone seen this or have any idea why it falls apart?

 - mitchg