I'm keeping an open mind about whether the 737NGX is yet fully stable. But whatever the answer to that issue, I suspect that some of the CTDs being reported are simple hardware problems. Some of the people posting about CTDs have overclocked their PCs. Remember that OCCT and other "stress testers" don't always reach the parts that FSX will reach. Those of us who have been around for a while know that FSX is an unusually demanding application even without add-ons. Every generation of new add-on aircraft stretches the limits a little further. Under this pressure, seemingly stable PCs sometimes turn out to harbour hidden instabilities. Sometimes it is a bug in the software or a genuine false setting (eg the HighMemFix that ******* found), but usually the software is either innocent, or a mere contributing factor. My advice is: before spending a lot of time fussing over software and settings, (i) run the PC and GPU at stock settings: if this gives a stable result, you know that the problem is with your o/c; (ii) change your settings to make the fan on your GPU run at 100% all the time when running FSX; (iii) hardware sometimes dies, usually without any immediate warning sign, especially if o/c'd. So if you still get a CTD at stock settings, try swapping-out the RAM and/or CPU and/or GPU and/or MB(assuming you have spares or old parts): if you now get a stable result at stock settings, then again you know where the problem lies; and (iv) only if you have 100% exhausted all possibility of hardware fault, start blaming the settings / software. In my case (a variant of many earlier experiences): my previously stable setup is a 975 @ 4.4GHz with 6Gb 1866 7-8-7-20 N1 RAM. OK for the MD11 and 747X. But the 737NGX would CTD after about 30 mins. I got better results by taking the RAM down to 1333MHz at 9-9-9-24 N2 and adding some voltage to the CPU. But this was only a sop, because a while later I got another CTD. So I changed the RAM sticks for some spares. Voila: problem solved (fingers crossed!) Rgds Tim

Wise words! I,ve had similar experience with my fsx system.I used to have ctd's in fsx all the time with my oc'ed i7 950 @4.3 Ghz, but after installing the NGX and subsequently tuning the cpu down to about 4.1 Ghz (and run fsx as an administrator), I run my fsx 100% crash free.I'll have to agree that more than a few CTD's reported are hardware (overclock) related.My advise would be to try it, it completely changed my experience. No more frustrations, and actually completing flights!