I have looked on the internet at this problem and most posts are over a year old, just wondering if a solution has been found recently.I am using FSX and various third party aircraft with a reasonable spec computer, see below. At varying times during a flight all the instrument will get flickering coloured vertical lines in them then the screen will freeze and will either shut down my monitor or I get the BSOD, the sound normally continues. The only pre-warning I have of this is the FPS starts oscillating from 30 to about 27 rapidly as indicated using FRAPS.When I go into Vista

Hi Glen,Ive had endless problems with BSOD's and Nvlddkm. It took extreme measures to fix it with the 17x drivers. There was never a problem with the 16x drivers. If you do the following it is entirely at your own risk (as I am writing from a rusty memory).1) Create a restore point.2) Download Driver sweeper and Driver Cleaner Pro.3) Using Device manager unistall the driver and graphics card.4) Reboot in Safe Mode and run the programs in 2).5) Reboot. Hopefully a standard VGA driver will install. Don't let it install an Nvidia driver (if it can find one).6) Try the contents of posts 15 and 29 here (also noting the part about bad RAM)http://www.vistax64.com/drivers/120889-nvl...sponding-2.html7) Using Device Manager update the graphics card driver using the option 'Search automatically for updated driver software'. The 178.13 driver will be installed directly from Microsoft.That fixed my problems (touch wood).

Hi HowardMany thanks for your helpLooking at that link it initially looks quite comlicated, but this nvlddmkm problem is driving me nuts so I think I'll give it a go. The last time I tried Drive Sweeper it somehow removed a file that prevented me connecting to the internet, I think I had to use system restore to fix it.Thanks again for your advice and the link.Glen

Don't know if this applies to you - but in my own experience this problem has always been the result of an unstable overclock: sometimes over-aggressive with the CPU, sometimes over-aggressive with the RAM - but never (sadly in some ways) a problem with the software.TimPS: passing Prime95 is NOT GOOD ENOUGH for FSX: it stresses parts of your system other applications do not reach ...

TimThats a good point, but as far as I'm aware the components are standard spec straight out of the box.Thanks for your help though.Glen

By all means try the software solution: goodness knows, we'd all love a clever fix. I'd be interested to hear your results, but you say you've tried a range of driver versions with no success, so I really doubt whether this will help. My only word of caution would be that it is very easy to screw up the entire installation by interfering with installed drivers; and personally I credit the Nvidia people with knowing how to write an installation routine that correctly identifies the files which need changing. I've had driver problems in the past, but they've always been to do with the quality of the driver, not defective installation routines.If the software fix does not help then I strongly suspect your problem has to do with your hardware not being configured quite the way FSX wants it - even though you haven't actually over-clocked. If so, then may I suggest the following routine?There are many things you could try here but - based on my own experience piecing together tips from others, mainly Nick_N - I would try the following checklist in this order:1. Try removing one of your GTXs. I only know what I've read - but if I recall correctly, the second card adds to the CPU's workload without adding anything worthwhile to the FSX party. Another reason for removing one of your cards is that it might reduce the burden on your PSU. 900W sounds like a lot, but if it's divided between 4 rails you might have a shortage of Amps where they count. "Quad rail" sounds good, but is usually bad: a "single rail" supply with 60Amps to deliver where they're needed is usually better than a "quad rail" with only, say, a maximum of 12Amps per rail.2. If you want a stab at a quick solution, try reducing the FSB by 5 or 10 MHz or so. The chances are it will give the components the little bit of extra headroom that FSX seems to like. In my case, before I discovered the tRFC trick (see (3) below), this was a good quick way of bringing stability without giving up very much performance, although it's irritating to have to concede any speed.If that doesn't work or you don't want to give up speed (and if you have the patience): 3. Using BIOS or Memset, increase tRFC by 5, 10, 15, 20 or even 30: see if that helps. tRFC is usually the "big" number in the Second Information of your RAM settings. This little trick has let me resume 480MHz FSB (achieving 4.33GHz CPU and 1601MHz RAM on my E8600), after having had to go down to 470MHz and less optimal RAM settings due to intermittent crashes much like yours. 4. If that doesn't help, check the BIOS to see what "strap" the NB is using to translate FSB MHz into RAM MHz. This affects the dividers available for the system RAM. Try using a different one and choosing a sensible-looking RAM speed at the new strap. For example: my DDR3-1600 RAM runs at full speed with a 200MHz strap, but it doesn't like any of the speeds from the 333MHz strap, even those slower than 1600MHz.5. If that doesn't help, try setting the command rate in your BIOS to 2N (rather than 1N): might show up as 2T or 1T on your BIOS.6. If that doesn't help, try relaxing the RAM's performance level by one notch: eg, from level 7 to level 8. You might have this in your BIOS: if not, use Memset.7. If that doesn't help, try relaxing the "First Information" settings of your RAM: eg, from 7-7-7-20 to 8-8-8-24.8. If that doesn't help, try increasing the NB voltage by one notch.9. If that doesn't help, take the NB voltage back down and raise the CPU core voltage by one notch.10. If that doesn't help, bring the NB voltage back up again by one notch (so that both CPU and NB are "one notch up").11. Attempt variants. Basically the idea is to take the RAM out of the equation by relaxing settings until you can be confident that any crashes are the fault of the CPU - in which case a touch more core voltage sometimes does the trick - and then tweak the RAM back to an optimal level. It's a hugely boring and time-consuming process and, ultimately, a matter of trial and error.Good luck.Tim

HowardI tried the software approach and for a short while and I thought it was going to work, FSX did seem a lot smoother (178.24) after clearing out the old driver debris. I have since had two CTD's, one happened just under an hour and the other after 1 hr 20 mins. Prior to cleaning the system I did find 6 copies of Nvlddmkm in the System32 folder. It was worth a go though, thanks for your help.TimI have contacted my computer supplier and they confirm nothing is overclocked. I will remove one of the video cards and see what happens and if necessary try a few of your simpler tweaks, if this doesn't work I will give up, remove FSX and just fly FS9. FSX is the only software causing this problem, I'll just have to wait patiently until FS11 comes out !!!Thanks to both of you for your time and effortGlen

Fingers crossed.Tim

Glen,I have had issues with nvlddkm.sys causing BSODs and display driver has stopped responding with the 178.xx series drivers. The 178.24's being the worst. The 178.13s were much more intermittent but none the less the problem was still there.I have revertted back to the 177.92 beta drivers which have been rock solid for me and no more BSODs or display driver has stopped responding messages.

Glen,I installed 178.13's via Device Manager. If you installed.24's were they downloaded via MS or were they from nVidia?

I hope your FSX sliders are not set to max. I had a similar problem a long, long time ago and I got it to stop simply by lowering the top scenery slider (Level of Detail) from the highest to medium. I could duplicate the error by returning this slider to the highest again. I have also turned off autogen as that's a frame rate killer too. Return your FSX settings to the default and see if the crashes continue (save your current settings first so that you can return to them in the future if this doesn't work). It's a memory allocation error and IMHO no current computer system today is capable of running FSX at max settings consistently w/o getting occasional crashes. Setting AI levels above the default will also tax your system to the max. I have a very similar system as yours (yours is a little more powerful with the QX9650 CPU) and run dual 768MB 8800GTX video cards (I suspect you have the 768MB memory on your cards too). Lowering the sliders will not reduce the scenery graphics quality if properly tweaked. BTW, nice system! Best regards,Jim

I think it may be FIXED :-)Firstly I would like to thank everyone that responded to my problem, its good to see there are some very helpful and knowledgable people out here who are prepared to spare some time to help others.Today I ran FSX with third party aircraft and ASX, after 3 hours continuous flying not one CTD, I then rebooted my computer and flew for another 2 hours without any problems, totally unheard of in the past.Unfortunately I did not complete Howards recommendations to the letter and after completely cleaning out the old drivers I installed the new Nvidia 178.24 using the downloaded Nvidia install program, this didn't work so I tried the beta 177.92 again that didn't work. I then went back deleted the drivers and cleared the driver debris with Drive Sweeper in Safe Mode, rebooted and updated the Video card drivers from Device Manager by letting it find the correct drivers on the internet, I assume via Microsoft. As Howard pointed out the 178.13 drivers were found and installed and the results when running FSX are as above.Having tried practically every fix available on the internet and most drivers from the 160's onwards it appears to be finally fixed. Many people seem to have found a personal fix for this problem whether it be software or hardware, for me its not using the Nvidia Install Utility but letting Device Manager install the drivers, something I have never tried before, why this cured my problem I don't know but for me it works.If I do get any further problems I will reply to this post, touch wood I won't need to !!Best RegardsGlen

Glen,Glad to hear you have sorted. Enjoy flying!!!! :)

Thanks for the update on this. I'm glad to hear that it was just a software problem. Even making due allowance for the different ways people set up and use their PCs, it is perplexing that similar symptoms are attributable to such seemingly different causes on different computers. Surely it "didn't oughta be this way".I'm now left wondering whether I correctly diagnosed the problem in my case - even though my solution has worked - or whether to strip everything down as you have, reinstall the drivers and push again for a more aggressive overclock. And so the cycle continues ...Tim

Tim: Your post was most helpful and provided a LOT of good information, in a single, central location on this forum. I've suddenly been having a lot of CTDs and BSODs lately in FS9 (EDIT: FYI, THATs FS9, folks, NOT FSX) and, although I think most of my problems are going to be from a bad sector in my hard drive, I also know I've been out on the edge with my CPU and memory OCing. I've backed off a bit the last couple of days with good results and no visible loss of performance, and most of my adjustments parallel what you've posted herein. It was good to know that I was on the same track as someone else in his diagnostics. In the end, we both may find our issues were grounded in other areas, but at least I don't feel like I'm just shooting blindly in the dark any longer.