My PC specs:
GPU: GTX 750 ti OC 2GB VRAM
CPU: Intel I5 3470
RAM: 8GB DDR3
I can't join in multiplayer and have stutters in singleplayer... I thought 2.5 was supposed to run better than 1.5 atleast in low settings?
Make sure that you are HOLDING the trim while pulling and when you have slown down then release! Also try using "Central Positioning Trimmer Mode" (if you dont already) and make sure you have "Rudder Trimmer" on (if you are not using pedals).
Ok try holding 35/40 degrees pitch and balance the altitude with collective.
EDIT: Also watch the bearing and try to compensate if stats changing too much.