Hey Pent,  are you using graph editor or motion modifier to do your expressions.  I've heard that makes a difference but I've never tested it.   I always get slow response or sometimes no response when I implement my expressions.  The model movement becomes jerky positioning clumsey.  I don't know why that is and that's with just the 30-40 expressions I mentioned.  I'd like to think my machine was fast enough who knows?