Kirstens S22 64bit build.
It is not currently the default download, as its still not as mature as the 32bit version and has to make a few concessions as I have not had time to fully tweak the libraries it uses.
However it may be better in heavy sims as it can address more memory, which is technically a limitation of the 32bit variation. And absolutely nothing to do with rampant uncontrolled meshy avatars and excessive triangle counts :)
You can grab the build here from the link or navigate to the files section of my sourceforge page.
Anyway feel free to experiment, remember to clear caches as this can cause conflict if a previous version is installed!