HiI hope this may be of some use to someone but I have recently been working hard at getting the stutters off of my fsx system. I run a quad core Intel PC with sli GTX graphics cards and 2 gb ram. In my case the critical step in getting rid of the stutters was to reduce the number of cores running to 3 using the affinityMask= switch. The program ran smoother with *less cores running but with more b lurries and on my system this gave the best cimpromise. I now get frame rates of 30 or so with most settings except ai traffic and autogen maxxed out and little stutter. Before this switch was stuttery as anything.Hope this is of useMark

Thanks Mark (and welcome!). I'll keep this in mind if the four core Santa ever pays me a visit :-)Gary