I currently have WinXP (32) with 4GB (2X2) of 1600M DDR3 (7-7-6-18). I have the 2GB switch in boot.ini and currently a NV 8800 GT GPU. (CPU is a Q6600). So, rather an old rig that I will update one day. I would like to firstly venture into a new GPU that gives me more than the 768M that I currently have, and wondered if Win 7 (64) could put my 4 GB to better use than XP is doing and would support a 1GB GPU? Given that I could use the Win 7 and the new GPU into a new rig at some later time this year, would it provide any benefit to install Win 7 at the moment? I had read that there is a relationship between the GPU memory size and the amount of system RAM that the OS can put to work, and that 768M was about the limit for a 32 bit OS given that i only has so much RAM that it can access. Thanks- Bruce.

you answer your question ,sir. Win 7 64 bit take advantage of 4 GB RAM , it give more 10-30% FPS depend on your system . I prefer that.Regard

With a 32-bit OS (XP, Win or 7) you can only use a total of 4 GBy, this means your OS + FSX + Video RAM all have to fit in 4 GBy.With a 64-bit OS (XP, Win or 7) you can use more than 4 GBy of RAM, but any 32-bit App like FSX will still be limited to 4 GBy (this includes the app itself and the address space footprint of the 32-bit compatibility engine (API) the 64-bit OS uses to run 32-bit Apps.I don't know the size of this 32-bit footprint, but I presume it is far smaller than the size of the 32-bit OS, as most of the 64-bit OS runs in 64-bit (and thus is not part of the 4 GBy limit), while the app runs in 32-bits.Also I don't know if with a 64-bit OS and a 32-bit App like FSX, the Video RAM (1 GBy these days, which is a lot) is also part of the 4 GBy limit for 32-bit apps, or not. Note the answer to this question could be different when running FSX in DX9 vs. DX10 modes, as in DX10 the Video RAM is vitualized by the OS.Somebody with more info please alaborate on this!Cheers,- jahman.

With a 32-bit OS (XP, Win or 7) you can only use a total of 4 GBy, this means your OS + FSX + Video RAM all have to fit in 4 GBy.With a 64-bit OS (XP, Win or 7) you can use more than 4 GBy of RAM, but any 32-bit App like FSX will still be limited to 4 GBy (this includes the app itself and the address space footprint of the 32-bit compatibility engine (API) the 64-bit OS uses to run 32-bit Apps.I don't know the size of this 32-bit footprint, but I presume it is far smaller than the size of the 32-bit OS, as most of the 64-bit OS runs in 64-bit (and thus is not part of the 4 GBy limit), while the app runs in 32-bits.Also I don't know if with a 64-bit OS and a 32-bit App like FSX, the Video RAM (1 GBy these days, which is a lot) is also part of the 4 GBy limit for 32-bit apps, or not. Note the answer to this question could be different when running FSX in DX9 vs. DX10 modes, as in DX10 the Video RAM is vitualized by the OS.Somebody with more info please alaborate on this!Cheers,- jahman.

Thanks to both of you for your replies.I was hoping that purchasing both Win 7 and a new 1GB card that this could be the humble start to a new system and that the Win 7 could enable a 1G GPU to function adequately using my existing 4GB DDR3 and Q6600 CPU. I plan on replacing the mobo (currently GA-X38T-DQ6), CPU and memory at a later time, which I know will provide the most of any potential to run FSX better. Having a 1GB card now might make some of those bigger textures work better, such as those that com with the PMDG B748i.Thanks, Bruce.