It's a memory leak issue... I also have this.can you tell time interval between frame drop.
Heap size grows every 0.5 -1sec by 10-20mb, when it grows too big the garbage collector runs to reduce the heap size, that causes the stuttering (complete freeze for me for 1 sec in VR, worst cases computer freezes...) without the plugin nothing of the sort happens. Would be really nice if this got finally fixed. Happens every 20-30ish seconds...