In general, the virtual printer was created with performance in mind. However, sometimes it can make sense to change some of the default settings to gain a little bit of extra performance.
Disabling the garbage collection in Ghostscript can sometimes improve the performance. This feature in Ghostscript was originally designed to be used for debugging purposes and not for general use. You can experiment with it and check if disabling it will help on your system.
You can disable the garbage collection by setting
GSGarbageCollection = no in the configuration files. The best place for this setting is usually the global.ini. Then it will affect all future conversions.