Hi, Both cards work on their own with the PMDG-737NGX. As far as SLI, FSX works fine with all default aircraft as well as the Level-D 767 and all other 3rd. party aircraft (QW, CS an so on) I install. The only aircraft that will not work is the PMDG 737NGX.

Well I was hoping I might be able to help by bouncing ideas around, but you've got me at a complete loss.

Hi, Join the club, your not the only one, I've been working the problem for the past week.

Mike If I've understood correctly, you first got your setup to work with a single GPU, then found it crashed when you added SLI? I'm sorry this is proving so frustrating and I'm just scraping around here but one of the things I've noticed is that the NGX does not like changes in the hardware config at least on my PC. For example, once I un-plugged my loudspeakers. I turned on the PC and tried to run FSX: result - CTD each time I tried to load the NGX, with an error reported in the PMDG-737NGX.DLL module. Took me ages to resolve because I didn't imagine that anything so trivial could have caused a CTD. Also, saved flights seem to produce a CTD if I try to load them without the joystick plugged in. So I suppose what I'm asking is whether you tried using the routine you used to get the setup working with a single GPU, but using both GPUs instead? Ie: make sure that the SLI setup is already fully operational by the time you install the NGX? Tim

Hi, I configured my system with a dual video board / triple monitor setup right from the get-go, I didn't make any changes to my system configuration until I found that I was unable to get the PMDG working, that's when I decided to alter my system in an attempt to isolate the problem. I have to perform another install, so I'll make absolutely certain everything is setup the way I want it before installing FSX and PMDG.

That's a lot of work with no promise of success. I'm waiting for the service pack before rebuilding from the ground up. If your system works with all other add ons but one, then its logical to assume your system is not the problem.

Mike, considering the issue is still on I would suggest you to install the OS, update it and install all the stuff except NGX. Then you can image your HD and you can start fiddling with NGX. If something goes wrong you can put the image automatically within few minutes and you can start to fiddle with NGX saving lot of times each time. It's not a solution but until you'll find it you can save a ton of hours.

Hi, Well, I've come to the conclusion that the PMDG 737NGX will not run on my system with a triple monitor setup. I have NO IDEA what the heck is going on. If the service pack does not fix the problem, I'll just have to do without the PMDG 737NGX aircraft. I give up.

At the risk of sounding a bit simple-minded, I really can't help but ask - have you considered that it may have nothing at all to do with the hardware?In my case, CTD issues turned out to be as simple as having an NGX default flight (something apparently you cannot do). I luckily figured that out before starting the process of uninstall/reinstall.

I had the problem with CTD on long haul flights only. I fly in windows mode so I can us two monitors. What fixed it for me was I shrank the window down ever so slightly and have not had CTD since. (touchwood)

Mike, don't give up. Beside imaging the HD that will let you save a ton of hours while experimenting I also suggest to get in touch with forumers who have the same or similar hardware config, so a multi monitor based one. 737 NGX is the best add on ever released for FSX so it deserves an extra effort. I know sometimes can be frustrating so I suggest to let 2-3 days pass by and then fight back again. Here for example -> http://forum.avsim.n...monitor-737ngx/ -

Hi, Well, I've come to the conclusion that the PMDG 737NGX will not run on my system with a triple monitor setup. I have NO IDEA what the heck is going on. If the service pack does not fix the problem, I'll just have to do without the PMDG 737NGX aircraft. I give up.

I have a similar set up (using 580's and the latest drivers). I did suffer a few CTD's until I lowered the AA settings. May have been coincidence as various hot fixes were also appearing at a similar time. Try setting all of you graphic settings (AA etc) to the minimum and see if the CTD's stop. Maybe you have tried this already.

Hi, Tried that as well, same CTD problem. There is nothing left for me to try, I'll just have to wait on the SP and hope it works. If not, I still have the iFly that works.

I'm sorry you're having to go through all of that. I guess I'm going to take a lesson from you and wait to do any major system software reinstallations until the service pack.

I'm sure this was covered during your support sessions, but I thought I'd ask just in case.Have you tried downloading & installing dx9 from the Microsoft site? I remember reading where that solved a few ctd's shortly after release.