I assume its a skin down load thing........
Over enemy field bogie (FW or 109 in this case) comes to a rannge circa 2k and my FR drops to 2 > 3 FPS (ie it freezes)and after a couple of secs returns to a normal mid 20 to mid 30 rate depending on view.
Video GUI settings at about 80% on both sliders.
NVidia FX5600 256 53.04 drivers
Quinqux AA plus other settings to "performance"
AMD +2500 @ 1700
512 RAM @ 133