There are some performance related fixes for OMEGAMON XE for z/OS that you may want to be aware of.
A couple of these relate to OMEGAMON monitoring storage and CSA utilization, and have potential impact in both the 3270 and Tivoli Portal interfaces. APAR OA37619 addresses cost of data collection and alerting for CUA, Classic and situations in the TEP interface.
APAR OA37647 has impact in the Classic and CUA interface.
APAR OA36726 addresses high CPU usage in the TEMS address space related to CSA analysis and monitoring.
Another interesting APAR is OA38126. This APAR relates to high CPU usage in the TEMS address space related to the cost of DASD collection specific to running situation alerts for DASD. As is often the case, the more data you need to collect, the more the potential overhead. DASD collection is always a potential issue because many shops will have multiple thousands of UCBs that need to be monitored. This particular APAR addresses that the DASD Devices workspace will collect information from both RMF and cache data sources. If a situation alert against this table of data does not require cache information and is able to do what is needed using just RMF data, then the cache data will not be collected.