There is information about resource usage of the standalone vs AUv3 as well as recommended devices on the Specs page. Hammond B-3X is going to run better on newer devices that have the horsepower to run a very complex app like this.
If you feel there is a global issue (or an issue you are having specifically) you must report that to IK Support so they can either get you up and running if it is an issue you are having specifically or recreate anything that may be global. As far as I know there is no global resource usage "bug" submitted to the devs but I'm not part of the tech support team (nor is this forum a medium for tech support as stated frequently including in the rules like at the top of each page and to which you agreed when signing up for the forum) so they would have more information and the ability to troubleshoot your issues and verify anything global to be officially reported to the devs.
Hammond B-3X is more than usable live (it has even been used live by the amazing Erik Norlander who needs absolute stability as he's a professional touring and recording musician).