Hello,I am dealing with a mysterious problem now for at least one year and I hope that here are some people who can help me to fix this.First of all I give you my current specs: Intel i7-2600, ASUS P8P67, 4 GB DDR3, GTX460, Creative X-Fi Titanium, Windows 7 Professional 64bit with all drivers up to date and finally FS9.My problem is as follows: I can lock my fps-rate to 60 or 30 fps and everything runs smoothly with standard Flight Simulator aircrafts (e.g. Cessna R172). No fps drops occur. But when I roll with the PMDG 737-800/900 (Ver.1.1) I experience heavy stuttering especially when turning on the ground :(. Also no fps reduction occurs. Although I am posting in the 737NG Forum I am experiencing the same issue with 747-400 as well. I really can´t tell you whether the same problem might occur with other add-on aircrafts because I have none to check. Is there someone who can help me to fix that? I am driving crazy.And again, I have to emphasize that I can never observe a low fps-rate.Thanks in advance!Tobias

Remember that there alot of other things going on besides visual rendering on an aircraft as complex as the PMDG. Locking to a high frame rate will force resources away from the other systems that are sharing your system at that time.Your system is working to provide 60fps and the turning of the ac (and other things) has to take a back seat, thus will have to wait for resource time causing stutters.I have less of a system than you do, but I will lock mine to about 19fps. I still get decent visual rendering without massive stutters.I hope this makes sense.