Our project is not that large (about 700 source files ignoring test cases) but highly modular being made up of 134 modules.
We adopted the Irida EAP for its Subversion support around build 3060 and find many of the other improvements since 4.5 add greatly to the tools productivity.
Sadly, the productivity gained through new features is offset by the degradation in performance.
We use dual Xeon PCs for our pair programming stations. IDEA, often after switching from one source file to another, will stop responding to the mouse or keyboard. When this happens one of the CPUs goes to 100% and it can take some time (30 to 40 seconds) for the IDE to recover. We have found that setting the CPU affinity of IDEA to a single processor reduces the frequency of the lock up but does not prevent it entirely. (5.0.2 seems to lockup regardless of the affinity setting, build 4049 seems to work OK with one CPU)
If we add a new module or change module settings, IDEA will pause for 10 to 15 seconds on pressing the “apply” button.
Today, when using IDEA, my machines twice ran out of virtual memory. Once on a PC with 1G RAM and the second time on my book with only 512MB. The vmoptions in the IDEA /bin directory are set to use max 256MB on the notebook and 392MB on the larger machine. Both occurred shortly after a checkin to Subversion but that may be coincidental.
Please let me know if there is anything I can do to help you determine the cause of these hangs or memory leaks.