Use this repro mission which spawns the classname defined in /functions/Core/fn_test01.sqf line 9 _spawncar = "B_MBT_01_arty_F" createVehicle _pos;
https://github.com/Fankserver/ArmA3-BugSamples/tree/master/18451
Big thanks to Fank for the repro mission and simplification of my original script!
Delete all class Sounds in a vehicle's config.bin (change http://pastebin.com/PFeM3SDw to class Sounds {}; for example)
Change simulation = "carx"; to simulation = "car"; in config.bin to disable Physx (old simulation from Arma 2)
Rerun the test and see that when Sounds and Physx is disabled that FPS doesn't drop with enablesimulation false.