We are using Japser to generate reports in our application We have upgraded from 5.0.1 to 6.4 to achive better performance but this is what we are seeing after few test runs. Jasper version : 6.4 JDK 1.7 Server : tomcat 7 , 3GB RAM Number of records : 850k Below is the memory consumption and CPU utilization when generating the report Looking for suggestions on how to reduce report generation time with lower memory consumption. We are using JRSwapFileVirtualizer. When virtualizer was not used, then time taken to generate report was better but we could not generate large reports.Should we use another virtualizer like Gzip virtualizer or tweak parameters for File Virtualizer like maxSize, blockSize and minGrowCount parameters.