Mystery solved! My _JAVA_OPTIONS environment variable was set to “-Xmx512MB”, which capped the memory at under half a gig. Removing this option caused it to fail to launch at all, which eventually led me to figure out that I was running a 32-bit JRE on my 64-bit virtual desktop. I downloaded a 64-bit JRE, uninstalled the old ones, and I’m back in business with 1824 MB of memory available in my designer. 