kimberlyRJ
Posts: 249
Joined: Thu Mar 06, 2008 7:35 am

FSX And 2GB Memory Limit

Mon Mar 30, 2009 10:24 am

Hi there

I have been having a few problems with FSX crashing on me. It happens every time FSX goes over 2GB...

I have been informed by PMDG support it’s because FSX is going over its ‘allocated maximum’ of 2GB.

The support person from PMDG who was very helpful said that I could increase the maximum from 2GB to 4GB – but then did not explain how to do it...

He did copy a link (see below)
http://msdn.microsoft.com/en-us/library/aa906211.aspx

But I cannot make head of tails of what it’s even suggesting I do.

My question is, how do you increase the memory allocated that FSX is allowed to use? Does anyone know how to do it?

Thanks for your help

Kimberly RJ
 
B727-200
Posts: 1008
Joined: Fri Nov 05, 1999 11:28 am

RE: FSX And 2GB Memory Limit

Sun Apr 05, 2009 9:55 pm

Hey Kimberlyrj,

I read through the article because I am suffering the same crashes, and yep, it was a page full of random words to me too, lol.

Hopefully there is someone out there who is able to interpret it for us "laypeople"?

B727-200.
 
UA772IAD
Posts: 1269
Joined: Sat Jul 10, 2004 7:43 am

RE: FSX And 2GB Memory Limit

Mon Apr 06, 2009 5:26 am



Quoting Kimberlyrj (Thread starter):
Hi there

I have been having a few problems with FSX crashing on me. It happens every time FSX goes over 2GB...

I have been informed by PMDG support it’s because FSX is going over its ‘allocated maximum’ of 2GB.

The support person from PMDG who was very helpful said that I could increase the maximum from 2GB to 4GB – but then did not explain how to do it...

He did copy a link (see below)
http://msdn.microsoft.com/en-us/library/aa906211.aspx

But I cannot make head of tails of what it’s even suggesting I do.

My question is, how do you increase the memory allocated that FSX is allowed to use? Does anyone know how to do it?

Thanks for your help

Kimberly RJ



Quoting B727-200 (Reply 1):
Hey Kimberlyrj,

I read through the article because I am suffering the same crashes, and yep, it was a page full of random words to me too, lol.

Hopefully there is someone out there who is able to interpret it for us "laypeople"?

B727-200.

This has to do with the command prompt:

BCDEDIT /set increaseuserva 3072 (go to run and type/copy this in)

It essentially increases your virtual memory above the 2GB set by Microsoft. It only works if you're operating system has more than 2G RAM.

The 3072 values means your operating system now has 3GB of RAM to use. Any more, and you're computer might completely crash.

See this site for complete details:

http://www.simforums.com/forums/printer_friendly_posts.asp?TID=25758
 
kimberlyRJ
Posts: 249
Joined: Thu Mar 06, 2008 7:35 am

RE: FSX And 2GB Memory Limit

Mon Apr 06, 2009 6:31 pm



Quoting UA772IAD (Reply 2):
This has to do with the command prompt:

BCDEDIT /set increaseuserva 3072 (go to run and type/copy this in)

It essentially increases your virtual memory above the 2GB set by Microsoft. It only works if you're operating system has more than 2G RAM.

The 3072 values means your operating system now has 3GB of RAM to use. Any more, and you're computer might completely crash.

See this site for complete details:

http://www.simforums.com/forums/prin...25758

It depends on how much RAM you have.

For example if you have 12GB like me then you can assign 4GB (or 4072) and I have had no problems at all.

It is worth noting that if you are going to tamper with the allocated max RAM settings for FSX you need to have SP2 installed and the process of upping the allocated RAM for FSX is more stable on a Vista plant form then XP.

Regards

Kimberly RJ

Ps. I am still in the testing phase at the moment, however I have noticed a slight improvement when upping the limit to 3GB, however it has become even more stable when upping to 4GB (which is the maximum).
 
B727-200
Posts: 1008
Joined: Fri Nov 05, 1999 11:28 am

RE: FSX And 2GB Memory Limit

Tue Apr 07, 2009 1:49 am



Quoting UA772IAD (Reply 2):
This has to do with the command prompt:

BCDEDIT /set increaseuserva 3072 (go to run and type/copy this in)

It essentially increases your virtual memory above the 2GB set by Microsoft. It only works if you're operating system has more than 2G RAM.

The 3072 values means your operating system now has 3GB of RAM to use. Any more, and you're computer might completely crash.

I hunted around and found this yesterday, gave it a go and it did improve the stability of the Sim (eg. no more OOM errors).

If I can ask a stupid question - is this now the default on my system or do I need to run this command each time I boot the system up?

Thanks,

B727-200.
 
comorin
Posts: 3857
Joined: Sun May 29, 2005 5:52 am

RE: FSX And 2GB Memory Limit

Tue Apr 07, 2009 2:16 am

Kim,

On a 32-bit Windows system, you can only address so much memory (4GB); the rest is just not addressable (usable). With 32 bits, and each bit having 2 possible values, you have 2*2*2*2*2*2*2*2*2*2*2*2*2*2*2*2*2*2*2*2*2*2*2*2*2*2*2*2*2*2*2*2 = 4,294,967,296 bits or 4GB of addressable space as the max possible. In other words, Windows cannot 'see' beyond 4GB, regardless of how much memory you have on your computer.

Within the 4GB limit, the space beyond 3GB is of questionable value as the OS (especially graphics) also needs address space outside of FSX. FSX is all about graphics, and using a high end graphics card makes a big difference, but will also eat up some of your address apace.

The only way to make use of more memory is to use a 64-bit operating system and run a 64-bit FSX if there is such a beast. Depending on hardware, you could go up to 128 GB RAM.

My guess is you're running Vista Home Premium 64-bit (since you have 12GB RAM). FSX is a 32-bit program so there isn't any benefit derived from all that RAM.


Hope this is helpful.

Cheers from NY!

Comorin
 
B727-200
Posts: 1008
Joined: Fri Nov 05, 1999 11:28 am

RE: FSX And 2GB Memory Limit

Wed Apr 08, 2009 5:00 am



Quoting Comorin (Reply 5):
FSX is all about graphics, and using a high end graphics card makes a big difference,

I hear and read much debate about this - whether a faster CPU or faster GPU will benefit. I am currently running an nvidia 8800 GTS (320mb), but want to try and get my hands on a 9800 series and/or a 200 series GeForce card to do some benchmarking.

With the addressing issue, I have worked out that my system sucks up about 850MB of the address space, which makes me wonder why I bothered with 4GB of RAM  Yeah sure

B727-200.
 
UA772IAD
Posts: 1269
Joined: Sat Jul 10, 2004 7:43 am

RE: FSX And 2GB Memory Limit

Wed Apr 08, 2009 6:45 pm



Quoting B727-200 (Reply 4):
I hunted around and found this yesterday, gave it a go and it did improve the stability of the Sim (eg. no more OOM errors).

If I can ask a stupid question - is this now the default on my system or do I need to run this command each time I boot the system up?

If it told you 'operation complete' or 'save successful' or something along those lines, then you should be okay. I don't know if automatic updates disables this. If you get any more OOM errors, then you know.

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