[en] The Event Builder and Level3 systems constitute critical components of the DAQ in the CDF experiment at Fermilab. These systems are responsible for collecting data fragments from the front end electronics, assembling the data into complete event records, reconstructing the events, and forming the final trigger decision. With Tevatron Run IIa in progress, the systems have been running successfully at high throughput rates, the design utilizing scalable architecture and distributed event processing to meet the requirements. A brief description current performance in Run IIa and possible upgrade for Run IIb is presented