We've had good success, working with support, by adjusting the buffers statement in the collector.config.xml, like:
serverbuffercount="100" serverbuffersize="2097152" />
or even bigger
<buffers agentbuffersize="32768" serverbuffercount="40" serverbuffersize="5242880" />
I understand your issue may be resolved at this point, but if you believe your collectors are using up more system resources than they should, there may be instrumentation set up for classes that have dynamic names, as this can increase the load on the collectors.
Just a thought, not sure if it's applicable here.