Same issue here (Sorry for bad english)
i7 4790k 16gb DD3
Samsung 840 pro SSD
XFX Radeon 7850HD OC 2gB
Saitek X52 Pro
TrackIR 5
Disregarding the graphics settings, I'm getting micro stutters every 5 or 6 seconds. CPU never goes above 40% and GPU over 35%, GPU mem use (in medium settings) goes to 1.6gb. When the micro stutters occur, the CPU usage goes DOWN, like inverted spikes.
I have tried LALT-ENTER for real full screen, vsync on and off, anything from low to high settings, the Mustang mod, and so...
I don't know what to try now...
Many thanks
PD. Most of the micro stutters ocurr when looking to the side of the canopy (?) (I use MIG21bis and F-86 Sabre). Out of the stutters, the game is smooth as butter