I'm running a I5 2500k @ 4.6, 8gb ram with a 2gb gtx770 just down loaded the latest nvidia drivers and am now able to set monitor refresh at 50hz so with 1/2 vsync in Inspector and frames limited to 25 in fsx I get the same smoothness as with 30fps and monitor at 60hz but which I could not always maintain 30fps,
this is great as my system has the headroom to run at 25fps all day long
I run with all the usual addons ie, NGX, orbx england, rex, uk2000 airports etx and AA 2x sgss with most sliders to the right
cheers
Adam