maximum RAM Prepare3d can use?

Any issues, problems or troubleshooting topics related to computer hardware and the Prepar3D client application
falcon127usa
Posts: 6
Joined: Sat Mar 24, 2012 12:33 am

Postby falcon127usa » Tue Apr 10, 2012 1:49 pm

What is the MAXIMUM amount of RAM prepare3d can use???



I think FSX can use 2 gig,... And ESP I don't know how much it can use.



FSX might be forced to use 3 gig maybe by modifying a file.



Shed any light?



Thanks

Falcon127usa

FSMP
Posts: 678
Joined: Sat Sep 25, 2010 9:38 am

Postby FSMP » Tue Apr 10, 2012 4:07 pm

MASSES of info on this subject on the Internet.



Simple answer is. FSX, ESP, P3D, by default, can only use 2 gigs of address space with a 32 bit OS.

That can be increased up to 3 gigs, using the "3 gig switch"/

The remainder of the 4 gig address space is used by the Kernel.



Things are a LITTLE better on a 64 bit OS, as (I beleive) the kernal exist in the 64 bit address space, outside of the 4 gig 32 bit address space, so the application may be able to use even more than the 3 gigs of the 32 bit address space. ???



Adding more PHYSICAL ram, does not increase this avaiable address space for these Flight Sim 32 bit applications.



IF you are interested in the details, try a few Google searches to get more infomation.



One like I just looked at, is reasonably clear and simle to understand



http://www.brianmadden.com/blogs/brianmadden/archive/2004/02/19/the-4gb-windows-memory-limit-what-does-it-really-mean.aspx



PERSONALLY, when I am running on XP 32, I use the 3 Gig switch, when booring up to use FSX or P3D, and have it set to give my applications 2.5 Gigs. This seems to be a good compromise for me, for the amount of addons I typically run in FS.



However, be prepared for the possibility of a few odd things happening with other programs on your PC, if you use the 3 gig switch.

( Most of these are not that well documented, so it can start to make your PC appear to be less stable, than it might be, without using the switch)



That being said, using the "3 gig switch" to give me 2.5 Gigs application address space, has stopped the OOM's I sometimes had, without the switch, when running multiple, large addons.










FSMP
Posts: 678
Joined: Sat Sep 25, 2010 9:38 am

Postby FSMP » Tue Apr 10, 2012 4:18 pm

Just checked my Boot.ini (XP)



Part of it is listed below



WINDOWS="Microsoft Windows XP Professional 2.5GB" /fastdetect /3gb /USERVA=2560 /NoExecute=OptOut /usepmtimer /PAE

WINDOWS="Microsoft Windows XP Professional 2.0GB" /PAE /fastdetect /usepmtimer /NoExecute=OptIn

WINDOWS="Microsoft Windows XP Professional 3.0GB" /fastdetect /3gb /NoExecute=OptOut /usepmtimer




I notice that at some time I must have set the /PAE flag for some of these boot option !!



Does FSX or P3D benefit in any way from the /PAE flag ???

Burkhard
Posts: 185
Joined: Tue Nov 22, 2011 7:51 am

Postby Burkhard » Wed Apr 11, 2012 3:20 am

Just to add, while on a 32bit system any simconnect client counts for the available user space, so reduces the amount of memory available to the sim itself, this does not apply to 64bit systems. For FSX, simconnect clients are 32 bit applications, so can grow to 2 GByte each on a 64bit system, for P3D they can be, if I'm not totally wrong, 64bit applications.

FSMP
Posts: 678
Joined: Sat Sep 25, 2010 9:38 am

Postby FSMP » Wed Apr 11, 2012 8:34 am



Quote:

Quote from Burkhard on April 11, 2012, 03:20

Just to add, while on a 32bit system any simconnect client counts for the available user space, so reduces the amount of memory available to the sim itself, this does not apply to 64bit systems. For FSX, simconnect clients are 32 bit applications, so can grow to 2 GByte each on a 64bit system, for P3D they can be, if I'm not totally wrong, 64bit applications.




Is there a 64 bit version of Simconnect, that can linked to a 64 bit Simconnect (out of process) application (exe) ?



I was not aware that 32 bit P3D could load 64 Bit simconnect dlls ? (without additional mechanism to achive this)



Can you explain again, in a different way, what 64 Bit application you are refering to ?

Burkhard
Posts: 185
Joined: Tue Nov 22, 2011 7:51 am

Postby Burkhard » Wed Apr 11, 2012 10:25 am

While, for every simconnect program for FSX I have to select the x86 code, this is not needed when linking against the Prepar3D simconnect DLL, and still is working From that I concluded the above.

FSMP
Posts: 678
Joined: Sat Sep 25, 2010 9:38 am

Postby FSMP » Wed Apr 11, 2012 1:30 pm

My understanding is based on the following Thread, from about 1 year ago. I do not think the situation has changed since then. :(



http://www.prepar3d.com/forum-5/?mingleforumaction=viewtopic&t=229



Geoff

virtuali
Posts: 517
Joined: Tue Sep 27, 2011 12:51 pm

Postby virtuali » Wed Apr 11, 2012 3:10 pm



Quote:

Quote from Burkhard on April 11, 2012, 03:20Just to add, while on a 32bit system any simconnect client counts for the available user space, so reduces the amount of memory available to the sim itself, this does not apply to 64bit systems.




Yes, on a 64 bit OS, every Simconnect out of process client ( and .EXE file ), even if they are still 32 bit apps, can allocate up to 4GB for itself so, it would make sense having more than 4GB of RAM, to at least allow many separate clients running without much troubles.



On top of that, on a 32 bit OS, the amount of VRAM in the video card will cut into the total 4GB addressing space too so, using a video card with more than 512 MB under a 32 bit OS is a very bad idea, because by subtracting from 4GB, the VRAM amount and the memory allocated by the sim, doesn't leave much headroom for all the rest of the process launched by the OS itself.
Umberto Colapicchioni - VIRTUALI Sagl
http://www.fsdreamteam.com


Return to “Hardware Specific Questions”

Who is online

Users browsing this forum: No registered users and 27 guests