I just ordered 8 more on Monday. That'll put me at 12 in this system. I couldn't pass up 8GB of DDR3 1600 for 50 bucks. I OCCASIONALLY use up all 4 I have now, but I don't do a whole ton of actual work on this computer.
i7 4790K - Z97 mATX - 16GiB DDR3 1866 - GTX 970 - 256GB 850 PRO - 500GB 840 EVO - HGST 3TB -Audioengine D1 - Audioengine A5+ - ATH-M50 - U2415 - Win8 Pro x64.