B737NGX Problems

Hey. Im a probe owner of the 737NGX. But i have some problems with it.1. Then i turn on autopilot, i have an issue when hdg is on and banking vs drops a lot( from 2900 to -3500).2. Then im using the plane my system seems to freeze about 10-20 sec, both on the ground and in the air. I have done the things said in the manual as good as i can.My system information is:CPU: Intel i7 950 3.07GHzRAM: 6 GBGPU: ATI Radeon HD 4800OS: Windows 7 64 Bit W SP1.Joystick: Logitech G940Keep in mind that im not an pro pilot, just an armature that loves to fly around in PMDG's great planes.