Look at "AudioHQ/SoundFont/Options/SoundFont cache". There is only one choice here: "Static caching". Now there exists an alternative way.
Besides dynamic patch caching, which allows to load only those SoundFonts which are currently needed, with Megafont you can also quickly create a compound SoundFonts, create patch lists for sequencers and expand your SoundFont cache size (on SBLive! only)..
Most of widespread sequencers are supported, there is also a Winamp plugin allowing to listen MIDI tunes with the GM banks which are exceed a static cache size.