I'm sure you would be more likely to get a response in the FSX thread, but I also had stutters with i7 and Win7. There's several work arounds.
1) Lock the framerate in-game. (comes with performance hit)
2) Lock the framerate with a 3rd party app like FPS_Limter. (no performance hit)
3) Set a Buffer Pool via the cfg to an extremely high value like 100-300MB. (needs lots of vram)
With only 512MB of video RAM you may only be able to get away with a 100MB Buffer Pool, but the higher you can go the better off you will be.
Also FSX responds best if you disable Hyperthreading as it may have issues with thread collisions due to faux threads being spawned. FSX does not support HT. With HT disabled set an Affinity Mask of 15 in cfg.
This is what I use with Autogen set to Extremely Dense and framerate set to unlimted, which is totally stutter free. The Buffer Pool is the magic tweak, and without that I must use a framerate lock at a value I can consistently achieve to eliminate the stutters.