With all this discussion regarding RAM allocation in reference to the operating system and videocard memory size, can anyone share their experiences using the NGX with a GTX580 3GB card?I have yet to purchase the NGX and am watching this forum with interest. Thanks Andrew Dixon

I see Windows 7 Professional 64-bit with SP1 in your tagline. Since you are running 64-bit you won't have to worry about the 3 gigabyte mapping issue. That only applys to Windows 32-bit. With your 8 gigabyte of system memory you should be golden.

Could be a potential issue. Even though you're on a 64b os, fsx can still only use 4gb. If the 3gb on your video card is part of that you could run into problems.

I see Windows 7 Professional 64-bit with SP1 in your tagline. Since you are running 64-bit you won't have to worry about the 3 gigabyte mapping issue. That only applys to 32-bit. Also with the 8 gb of memory you have you should be golden.

But as Ryan said, the card use at most use some 60% of it and that should be 1,8GB which have to beadded to FSX VS ( Only FSX can in a heavy scenery reach some 2,8 GB). All in all, he could pass that 4GB (2,8+1,8) that FSX can utilize at most and be suffering of OOM in that case. (FSX is still a 32 bit system even if the 64 bit OS can utilize, a hell lot of more VS of GB) My privat toughts. I could be wrong about the adding thing though. Anyway, why buy such a powerful GPU? Maybe you he is a gamer with a lot of such as Battlefield and....then I can understand it. / Leffe

Could be a potential issue. Even though you're on a 64b os, fsx can still only use 4gb. If the 3gb on your video card is part of that you could run into problems.

Where are you getting this from? FSX has nothing to do with the mapping of Video Card memory. The mapping only comes into play with 32-bit Windows because Windows would have to map his 3 gb Video Card Memory to the first 4 gig of System Memory. In that situation he would only have 1 gig of system memory available. 64-bit Windows does not have this limitation so it is a moot point in his case. Another good reason to be on 64-bit windows.

Where are you getting this from? FSX has nothing to do with the mapping of Video Card memory. The mapping only comes into play with 32-bit Windows because Windows would have to map his 3 gb Video Card Memory to the first 4 gig of System Memory. In that situation he would lose 3 gig of his system memory and only have 1 gig left. 64-bit windows does not have this limitation so his 3 gig video card would have no issues on 64-bit.

I'm getting thisfrom the 2 or 3 other topics started yesterday about this very thing. Maybe I'm misunderstanding you, but your post appears to suggest that having a 64-bit os means fsx can have all the memory it wants. It's still a 32-bit app.

I'm getting thisfrom the 2 or 3 other topics started yesterday about this very thing

In that case I would go back and re-read everything again. The mapping issue only applys to 32-bit windows and would only cause a problem in that situation. He was asking about the memory mapping issue. Yes FSX is a 32-bit application and will only use 4 gig of memory. However having an extra 4 gig of system memory means that FSX can use whatever it wants outta the 4 gig and he has another 4 gig for whatever else he wants to run while FSX is running. Just cause FSX will only run 4 gig max doesn't mean the rest of your system can't take advantage of the extra memory. Because it can and it will. Heres a direct pull off the Microsoft site.

Various devices in a typical computer require memory-mapped access. This is known as memory-mapped I/O (MMIO). For the MMIO space to be available to 32-bit operating systems, the MMIO space must reside within the first 4 GB of address space. For example, if you have a video card that has 256 MB of onboard memory, that memory must be mapped within the first 4 GB of address space. If 4 GB of system memory is already installed, part of that address space must be reserved by the graphics memory mapping. Graphics memory mapping overwrites a part of the system memory. These conditions reduce the total amount of system memory that is available to the operating system. The reduction in available system memory depends on the devices that are installed in the computer. However, to avoid potential driver compatibility issues, the 32-bit versions of Windows Vista limit the total available memory to 3.12 GB. See the "More information" section for information about potential driver compatibility issues. If a computer has many installed devices, the available memory may be reduced to 3 GB or less. However, the maximum memory available in 32-bit versions of Windows Vista is typically 3.12 GB.

For Windows Vista to use all 4 GB of memory on a computer that has 4 GB of memory installed, the computer must meet the following requirements:The chipset must support at least 8 GB of address space. Chipsets that have this capability include the following:Intel 975XIntel P965Intel 955X on Socket 775Chipsets that support AMD processors that use socket F, socket 940, socket 939, or socket AM2. These chipsets include any AMD socket and CPU combination in which the memory controller resides in the CPU.The CPU must support the x64 instruction set. The AMD64 CPU and the Intel EM64T CPU support this instruction set.The BIOS must support the memory remapping feature. The memory remapping feature allows for the segment of system memory that was previously overwritten by the Peripheral Component Interconnect (PCI) configuration space to be remapped above the 4 GB address line. This feature must be enabled in the BIOS configuration utility on the computer. View your computer product documentation for instructions that explain how to enable this feature. Many consumer-oriented computers may not support the memory remapping feature. No standard terminology is used in documentation or in BIOS configuration utilities for this feature. Therefore, you may have to read the descriptions of the various BIOS configuration settings that are available to determine whether any of the settings enable the memory remapping feature.An x64 (64-bit) version of Windows Vista must be used

Paul!....FSX can only use up to 4GB of memory, but the 64-bit OS can use up to 24 or is it 32GB.FSX is still a 32-bit application. A 32-bit system can only use up to 4GB and the FSX and OS have to share this. A 64-bit one don´t have to bother with the OS, FSX can use those 4GB alone.....that´s why a 64-bit is better. I have 16 GB of memory I know, but that amount won´t help FSX I know, but I´m multitasking all other stuffwhen I do other thing. / Leffe EDIT: Read Ryan´s post here # 81 I think it washttp://forum.avsim.n...el/page__st__75 Ds.

The Vram that FSX uses comes out of the VAS FSX is able to use. Being a 32bit application that's only 4GB. So if it uses 1.5GB of VRam, there will only be 2.5GB of VAS left for FSX, which could cause problems.

I'm missing something here? I have the same card but it is not 3GB. Do you have 2 of them? http://www.geforce.com/Hardware/GPUs/geforce-gtx-580/specifications

There are 2 versions. A standard (1.5GB?) version and a 3GB version

There are 2 versions. A standard (1.5GB?) version and a 3GB version

Mine are 1.5, so yes

Some differing opinions here. I find this ironic, my $650.00 GTX 580 bought especially for the NGX may be an issue. This is why I would like comment from anyone who has a 3GB GTX 580 and has used it with the NGX.Maybe the recommendation from PMDG should be a card with no greater memory than 1.5GB? Andrew Dixon

Okay my fault Mr. Ken your right about the VAS and FSX I looked it up. My Apologies. (Egg on face now). Just proves my point about 64-bit being superior though. Throw FSX and the NGX in the trash and get a 64-bit Flight Sim! I hear X-plane is coming out for Christmas and that they might make it 64-bit in SP1.

Fingers crossed for Flight