In Java 6 -Xincgc simply translates to: -XX:+UseConcMarkSweepGC -XX:+CMSIncrementalMode -XX:+CMSIncrementalMode causes more frequent, smaller pauses. It was

In Java 6 -Xincgc simply translates to: -XX:+UseConcMarkSweepGC -XX:+CMSIncrementalMode -XX:+CMSIncrementalMode causes more frequent, smaller pauses. It was designed for low CPU core count, small heap size applications where your willing to pay a CPU premium to gain better response times. It is specifically not recommended for 2+ CPUs and/or large heap sizes. With large heap sizes you'll be paying a large CPU penalty and if your are using / freeing a lot of objects it may not be able to "keep up" with its short pauses resulting in the heap filling up quickly.