Scaling network intrusion detection to high network speeds can be achieved using multiple sensors operating in parallel coupled with a suitable load balancing traffic splitter. This paper examines a splitter architecture that incorporates two methods for improving system performance: the first is the use of early filtering where a portion of the packets is processed on the splitter instead of the sensors. The second is the use of locality buffering, where the splitter reorders packets in a way that improves memory access locality on the sensors. Our experiments suggest that early filtering reduces the number of packets to be processed by 32%, giving a 8% increase in sensor performance, while locality buffers improve sensor performance by about 10%. Combined together, the two methods result in an overall improvement of 20% while the performance of the slowest sensor is improved by 14%.