Hi, I will try it tonight... What do you mean by lack of sufficient memory ? Is it an Hardware issue ? Aren't my 8GBs RAM enough ? Or is it because I have too many applications running at the same time ? Could it be a problem with my config ? Thanks for your help, Grégory Scyboz

You only get 4GB of Virtual Address Space for 32 bit programs and, when that runs out, FSX will crash.  FSX does not get to use it all.  So fsx will not be using all of those 8 GB's of RAM.  The whole issue about VAS is very complicated and I have a hard time (as well as other experts) to comprehend it.  The best explanation I have seen so far is in the PMDG 777 Intro Manual which is quoted, in part, as follows:

 

"FSX is a 32-bit application. Even under the recommended Windows 7 64-bit operating system, the FSX.exe process always faces the same mathematical limitations that all 32-bit applications do. One of these is a 4GB hard limit on something called “virtual address space” (VAS). When FSX crashes with an error message saying that your computer has run out of available memory (commonly called an “OOM” in the sim community), it’s actually talking about VAS, not physical memory like the amount of RAM in your system. Customers who have huge amounts of RAM like 16GB or 32GB are often baffled by this message for good reason – they certainly aren’t running out of physical memory. Microsoft probably should have made the error say “The application has run out of virtual address space.” instead of the vague “memory” term.

VAS is effectively a preallocation of everything the simulator can potentially access during a flight and will fluctuate over the course of using the simulator as you fly between different areas. Note that VAS is *NOT* the same thing as the “virtual memory” swapfile that you can set the size of in the Windows system options – they are two very different things and having a large virtual memory swapfile does not protect you from the 4GB VAS limit. The mathematical limit itself comes from the definition of “32-bit” – a bit is the most basic data structure in computer science and it can have two values, a 0 or 1, which can mean all sorts of things like true or false, on or off etc. This is why at the core a computer executes “binary” code. The amount of VAS a 32-bit process can access can be calculated by raising the number of possible values for each bit (2) to the power of the number of bits available (32). So 232 equals exactly 4,294,967,296 bytes (not bits). When you do the rest of the conversion math this value comes out to exactly 4 gigabytes of potentially addressable memory for a 32-bit process.

The reason we recommend using a 64-bit operating system like Windows 7 64-bit is due to the fact that it can give FSX.exe that entire 4GB block of VAS. In 32-bit Windows the default is a maximum of 2GB of VAS for FSX and 2GB reserved for the operating system. This can be increased to 3GB for FSX through an edit to the boot environment configuration (“the 3GB switch”), but this is still 1GB lower than you’ll get with the 64-bit version of Windows and it makes both OOMs more likely and OS crashes more likely because it reduces the amount of VAS the OS itself has to work with. 32-bit versions of Windows can also only ever access 4GB of total physical memory, so if FSX is using 3GB itself, there’s not much there for the OS and other applications. 64-bit Windows does not have this limit and with a lot of RAM you can essentially run as many other applications outside of FSX (browser, weather apps, flight planners etc) as you want with no effect on the system. There is literally no reason not to run the 64-bit version of Windows 7 on an FSX simming PC."

 

 

I found it on internet : http://answers.microsoft.com/en-us/windows/forum/windows_other-windows_programs/problem-event-name-bex-error-message/cf5baf73-0877-4070-abfb-a2c3a17a9e10 "right click on my computer go to properties click on advanced system settings under performance, click settings click the Data Execution Prevention tab, and then click Turn on DEP for all programs and services except those I select. click Add, browse to the executable file for the program and add it." Could it really solve the BEX problem ? Best regards, Grégory

Go ahead and try it.  You will get a message that tells you it is impossible for FSX to do this.  It would be a great world if the fix for BEX's was as simple as turning off DEP for FSX.  There is no known solution to BEX/StackHash errors other than reinstalling Windows and FSX (which I ended up doing) but some have accidently fixed their problem by lowering fsx/display driver settings, rebuilding the FSX.cfg, changing voltages in the BIOS, disabling all scenery addons in the Scenery Library, and/or shutting down FSX only in Windowed Mode and starting up in Windowed Mode but never in Full Screen.

 

Best regards,

Hi Jim !

 

A little feedback coming up

 

So, today I flew twice. For the first try, I flew again from Zurich to Berlin, but this time, without both Aerosoft sceneries. It worked well and my sim seemed stable. But after my landing at Tegel airport, I wasn't convinced at all, because of the long crash history I have behind

 

So I tried a second flight, this time from Cologne to Berlin AND with both Aerosoft sceneries. It also worked out.

 

So now, what I did is follow some of your advices like to shut down and start fsx in windowed mode and to disable all scenery add-ons but the departure and arrival airport.

 

And so far, it worked. But I'm still not convinced, so I will update you on my next 3-4 flights until I'm sure my fsx won't crash anymore !

 

Anyway, thanks a lot for all these advices and also for the very interesting explanation about VAS.

 

Best regards,

 

Grégory

 

 

Anyway, thanks a lot for all these advices and also for the very interesting explanation about VAS.

 

Finding the causes of most CTD's is a matter of conducting an investigation and you are on the right track(s).  If there was a solution that would work for everyone, I would definitely post it but all computers are set up differently, have various tweaks or do not have tweaks, some have overclocks, some don't, device drivers are up-to-date in some computers and in others, not.  Good luck!

 

Best regards,

For anyone having some OOM crashes, I also found this very good explanation about VAS and how FSX uses it ! Even how to monitor your VAS usage and everything ! (http://#####.wordpress.com/fsx-oom-and-addon-vas-usage)

 

Best regards,

 

Grégory