Hi all,I've read almost everything about stutters in this and other forums and have tried out many and more of the suggested tweaks and/or de-activations of background programs etc. etc. -- but with only marginal stutter decreases. This also includes decreasing the Latency of my "VGA compatable controller (VGA)" from 264 to 64.However, nobody seems to name the basic fact that all FS versions structurally use (almost) 100% of the resident processor's capacity even when parked at e.g. an addon airport with nothing in the vicinity actually moving. This 100% processor load automatically means that as soon as something does begin to move e.g. the visible scenery when you begin to taxi, the load on the processor immediately excedes it's maximum, resulting in short reductions of frame rates which, with some "heavy" sceneries, can sometimes even be experienced as "stutters". These stutters also occur when flying at low altitudes over other "heavy" scenery types especially at the moment when new ground texture objects at (close to) their maximum detail, come into view. It is for this reason that viewing your landing in "Instant Replay" mode and "Spot Plane View", is especially notorious for stutters because of all the moving "heavy" (addon) scenery objects at close range, including those of your own aircraft, and in full screen view. Under these conditions the processor is simply swamped with work and must resort to the allocation of priorities and work ques with resulting extreme frame rate variations and ...... stutters. O.K. all you technical experts, I agree with you in advance that there can be many more additional reasons and partial cures for stutters but I firmy believe that the resident processor capacity is the main one for which the only real remedy at this moment in time, seems to be upgrading your machine to one with the fastest possible 64bit Intel processor, FSB, memory, motherboard chipset, etc. etc.A dual core processor is not really necessary for FS because you will find that one will always be at it's maximum load while the other is just loafing and not really contributing to the fastest possible FS frame rate effort. Even FSX in combination with Windows Vista does not seem to be able to put both cores to work in parallel, at least not as far as I can see at this moment.Comments are welcome.HansWindowsXP Home.FS9 (with huge addon sceneries and aircraft) running on a P4 3.0Ghz 800 FSB dual core/channel processor.2Gb Corsair Twinx matched pair 400 FSB memory.Gigabyte GA-8KNXP Titan Motherboard/Intel 875P chipset.GeForce 6800GS graphics card AGP 8X.

I completely removed Mcafee and the stutters seem to have finally disappeared (or greatly reduced). I'll do more test to confirm.I've been using Mcafee since "day one". It's a constant job for me to tweak to get rid of the stutters. It never occured to me that Mcafee might be a factor since I disable it with FSautostart.Thanks guys for this informative thread!Jason

I have been using Free AVG Anti virus tool on my 2 FS rigs. Takes care of virus coverage, updates easily and does not get in the way. I usually Fly with it on because I forget to turn it back on (lord help me remember to put the gear down when I finally get to learn to fly retractacle gear aircraft in the RW.) Have not noticed a difference either way.

With Mcafee gone, I tried three popular freeware antivirus: AVG, AVAST and ANTIVIR. For me AVAST is no go because it has the most running services and FSAUTOSTART can't even kill all of them. The other two are both very good. ANTIVIR reported one of the Flightscenery .exe files as "trojan". That made me think it's "too sensitive". I also FEEL that I have more obvious stutters with ANTIVIR. That's just a feeling. Anyway, I settled with AVG. It seems to be very light on my PC and I can completely shut it off and restart with FSautostart.