Hello everybody,here is an update on my troubleshooting efforts:1. It was not DX9 vs DX10 preview, as I had suspected ... flew KSFO-PHNL with MD11X, on DX10 preview. FSX froze after about 2:30 (no CTD, just froze, required termination using task manager). Then tried PGUM-RJBB with MD11X, on DX9 (ignoring the stroboscope during the first 10 secongs of the intialisation), no other programmes running - FSX froze after 2:10 (as before, no CTD, just froze, requiring termination using task manager). Either I was lucky enough on my previous attempt (KMSP-KEWR) to land just before it froze ... or --> see 3.2. Repeated the same flight, PGUM-RJBB, with the same flight plan made by FS Commander and saved in PMDG format, with the Queen 744X, on DX9. Smooth flight all the way to Osaka... This proves that neither flight plan nor scenery files nor AFCAD files are responsible for the freeze. I did, however, observe the autobrakes malfunction on landing, as reported by many 744 users in this forum, despite hand-flying on ILS 06 to touchdown and positively pulling Saitek throttle to idle plus hitting <F1> to make sure the Sim recognizes throttle idle before going into reverse. So much on the claims "user hardware" which I've seen here too... please everybody, try and report your results. Let us not make things worse by guessing.3. The common denominators of both recent freezes are a. flying the MD11X (no matter whether DX9 or DX10) and b. the fact that both flights included long transoceanic legs, far away from land and towers. Now that I have confirmed that the Queen can do what the MD11 cannot under identical circumstances, the next step will be to try a flight with the MD11 over a distance of more than three hours (I am thinking of KSFO-KORD) over land. Then we shall know more.Sigmar Stadlmeier @ LOWL/LNZ

3. The common denominators of both recent freezes are a. flying the MD11X (no matter whether DX9 or DX10) and b. the fact that both flights included long transoceanic legs, far away from land and towers. Now that I have confirmed that the Queen can do what the MD11 cannot under identical circumstances, the next step will be to try a flight with the MD11 over a distance of more than three hours (I am thinking of KSFO-KORD) over land. Then we shall know more.

O.K., now we do know more... first attempt on DX9 failed after only 15 minutes out of KSFO when opening the FSX menu to change weather settings - FSX accepted changes but failed to continue after hitting O.K. --> the lower half of the screen went black, the upper half went into stroboscopic flickering. Terminated FSX, changed to DX10 preview mode, restarted flight, set up airplane and FMC again (KSFO-KIAD, coast-to-coast) and -- made it into KIAD without any problems whatsoever (weather changes via FSX menu included -- and yes, lest I forget, autobrakes working as they were supposed to, as opposed to the Queen). So DX9 vs DX10 does contribute, at least with the nVidia GTX 275. Any detailed conclusions as to the MD11 are certainly airplane-specific and will be posted (after some more experimenting with FSX settings) in the appropriate MD11-forum, but two general questions remain:1. This time the flight remained over land, always in range of a tower... we know the issue which arises with the Queen after longer flights over water, screens in the virtual cockpit freezing, FMC in VC not accepting any input anymore - but in the 2D cockpit the Queen continues to function normally, and switching to 2D will update the 3D displays. Is the same FSX issue also troubling the MD11 but with more severe consequences? If so, a. why more severe consequences for MD11 than for 744? b. Has this never been observed during beta testing?2. Ryan Maziarz, a member of the PMDG support team, has posted his personal opinion under this thread that Windows 7 might be more appropriate as an OS than Vista 64 bit, while some others claimed that memory-related issues would prevail under W7, suggesting XP 64 bit instead. What has the OS got to do with this over-land versus over-water problem? More specific, has anybody else ever observed the same thing, sim sessions involving flights over water freezing and/or crashing, while sim sessions involving longer flights over land running fine (all other things being equal), and if so, what was the system environment like?Sigmar Stadlmeier

O.K., now we do know more... first attempt on DX9 failed after only 15 minutes out of KSFO when opening the FSX menu to change weather settings - FSX accepted changes but failed to continue after hitting O.K. --> the lower half of the screen went black, the upper half went into stroboscopic flickering. Terminated FSX, changed to DX10 preview mode, restarted flight, set up airplane and FMC again (KSFO-KIAD, coast-to-coast) and -- made it into KIAD without any problems whatsoever (weather changes via FSX menu included -- and yes, lest I forget, autobrakes working as they were supposed to, as opposed to the Queen). So DX9 vs DX10 does contribute, at least with the nVidia GTX 275. Any detailed conclusions as to the MD11 are certainly airplane-specific and will be posted (after some more experimenting with FSX settings) in the appropriate MD11-forum, but two general questions remain:1. This time the flight remained over land, always in range of a tower... we know the issue which arises with the Queen after longer flights over water, screens in the virtual cockpit freezing, FMC in VC not accepting any input anymore - but in the 2D cockpit the Queen continues to function normally, and switching to 2D will update the 3D displays. Is the same FSX issue also troubling the MD11 but with more severe consequences? If so, a. why more severe consequences for MD11 than for 744? b. Has this never been observed during beta testing?2. Ryan Maziarz, a member of the PMDG support team, has posted his personal opinion under this thread that Windows 7 might be more appropriate as an OS than Vista 64 bit, while some others claimed that memory-related issues would prevail under W7, suggesting XP 64 bit instead. What has the OS got to do with this over-land versus over-water problem? More specific, has anybody else ever observed the same thing, sim sessions involving flights over water freezing and/or crashing, while sim sessions involving longer flights over land running fine (all other things being equal), and if so, what was the system environment like?Sigmar Stadlmeier

Sigmar, I do not want to ruin your day or rain on your parade but I am not sure where you are going here? Black screens, white screens and flashing screens and their causes and existence within FSX are wide spread, reoccurring and well documented. Your testing water versus land if I understand correct is not valid. The reason they can never be valid is because these issues can and have occurred in so many varying scenarios that you do not have a control base. You will conclude nothing by your testing that cannot simply be discounted by the simple fact that the issue has been known to occur regardless of land flight or water flight. I myself was able (using Vista 64) to get a white screen/flashing screen/ stroboscopic screen simply sitting at any airport using FSINN. Every time I opened the FSINN consol or nearly every time bang something would happen.These occurrences while not specific to PMDG do seem to be magnified in use of PMDG products and do seem to be worse with the MD11. The issues being more prevalent with PMDG are well documented therefore any exercise by you trying to prove that they occur more often in the MD11 or whatever are redundant. Equally non exclusive is the fact and well documentation that these issues do in fact occur outside of PMDG products, they occurred with me on other aircraft.Additionally white screens/black screens/stroboscopic screens are well documented as occurring outside of flight simulator, simply Google black screen and see my point.I posted a link to tuning your system that may afford some relief in these occurrences. I also suggested that removing 4GB of your RAM would be better for FSX although I do appreciate the heartburn that such a recommendation may carry. Nobody likes to be told that bigger isn

Sigmar, I do not want to ruin your day...

Thanks, Gary, you were not ... at least this whole exercise has confirmed that the more memory-hungry the plane (MD11 certainly being so) the greater the problems become, which clearly points away from PMDG and to the OS and its way to manage RAM available. The problem for me was that I did not know even where to begin, precisely because these issues do arise under so many different environments. First, now I know the limits within which even MD11 runs well on my system, second, I could confirm that other PMDG products suffer much less from these issues (I am curious how the 737X family will behave once it comes out...), third, it tells me ho to proceed with my OS, and finally I still hope that this thread was helpful to some (I presume many) others who are just as confused as I were by the abundance of hits one will get when doing a forum search.Sigmar

EPILOGUE: http://forums1.avsim.net/index.php?showtopic=249782The buffer pool setting in fsx.cfg seems to be the key: Reducing this to 500000 eliminated all issues dicussed here.Sigmar Stadlmeier

EPILOGUE: http://forums1.avsim.net/index.php?showtopic=249782The buffer pool setting in fsx.cfg seems to be the key: Reducing this to 500000 eliminated all issues dicussed here.

... EXCEPT the freezes over water. And moreover:Just changed my OS from Vista 64 to W7 64, as suggested by some here. Better overall performance, but still issues with the MD11. Just froze on final after a longer flight, and though I had suspected some issues and saved the flight on regular intervals I was unable to load the last save ... crashed FSX every time I loaded it. That is the net result of - literally - DAYS of work, wasted time and wasted money. I am sorry, but I am not going to waste any more valuable resources on an essentially broken product. For me the PMDG MD11 thus will share the fate of its real-life counterpart, which likewise never could fulfill the promises of the marketing people of McDonnell Douglas. Do better next time, PMDG.Sigmar