I see the 3GB switch can be used, which is apparently built into acceleration, so I am wondering if anybody has before and after experience with using more than 2GB? I will be putting together an E6850 system soon, and I don't want to drop the extra cash on memory unless there is a noticeable difference. Thanks

Possibly you or the moderator could drop this question over in the Hardware Forum for a response... I would also like to know. I have 4 Gigs. I know that Vista only recognizes about 2.85 max, or something like that. I am not computer "smart" so I don't know if there is anything that can be done to take advantage of more. But I certainly would like to know.Steve

A 32-bit system can only address 4Gb of physical mmemory. Allocating 3Gb to an application leaves 1Gb for everything else - including the operating system etc.I understand that that this may not be enough for high-performance video cards that may require a csignificant amount of physical memory.

The way I understand it is the video card memory is part of the 4GB total.If you have 3 GB RAM and a 756MB video card - you have 3.756 GB of memory for the OS to use for all purposes.If you ahve 4 GB RAM and a 756MB video card - you have 4 GB of memory for the OS to use for all purposes.

Doesn't that support my point?If you have 4Gb of RAM and use 756Mb for a video card and allocate 3Gb to an application then surely the operating system would only have 244Mb available for its own use? This could be inadequate.

I believe the northbridge masks much of the physical address space in the region of about 3.3 - 4.0 Gig. On a 64 bit OS any physical RAM at that address can be remapped above 4G, but in 32 bit OS the memory can't be remapped and so isn't visible. (I think there may be some methods in which 64 bit drivers can get around that.)Separately, each app gets 4Gb of virtual address space, and I believe it is in this space that the video memory gets mapped so the application can't use it for it's own storage, even if it is large address space aware (able to use virtual address above 2Gb).scott s..

If you go to vista 64bit it will recognized all your ram and is a much faster operating system. I have 4gigs of high end ram and I'm getting high fps with the sliders moved pretty much to the left. I keep AI traffic lower because I don't want to do a lot of go arounds.Make sure you use the vista patch before any 3rd party add-ons or you will get a memory error.Capt.Mac

I wish I could provide the answer to your question as all the other responses are not addressing it, with the exception of Capn Mac.I can tell you this: I have measured the amount of system and video memory used on my XP install of FSX and have not reached 100% of 1 Gb and 320 Mb, respectively. It has been very, very close to 100% though. I'm confident higher slider settings and higher res textures would more than max out my system.

The problem I had with going over the 2Gig was...I had to throttle down my over clock that I had done.I have my dual Core running at 3.5Ghz. and when I increased from 2Gig to 4Gigs.. It didn;t like my OC.So the question then was... do I have my 4 Gig running at 2.4Ghz or do should I just go with 2Gig memory and the system running at 3.5Ghz.I chose the 2Gig + 3.5Ghz and returned the 2 Gig memory.I am really curious to know from Over clockers where they have 4Gig memory + their over clock intact!Manny

>>I am really curious to know from Over clockers where they have>4Gig memory + their over clock intact!>>>MannyThey might be using 2 sticks, whereas you were probably using 4 sticks when you tried your overclock. Just a guess...RhettAMD 3700+ (@2585 mhz), eVGA 7800GT 256 (Guru3D 93.71), ASUS A8N-E, PC Power 510 SLI, 2gb Corsair XMS 3-3-3-8 (1T), WD 150 gig 10000rpm Raptor, WD 250gig 7200rpm SATA2, Seagate 120gb 5400 rpm external HD, CoolerMaster Praetorian

Yes.. I was using 4 sticks.Are you saying,.. If I had used 2G X 2 I may have been ok?Manny

Hi Manny,I'm using 4 1 gig sticks under Vista Home Premium... and it didn't seem to affect my overclock. I added two sticks after I was running the E6700 at 3.6 gigs. I still haven't concluded from this thread whether or not (at least the 4th stick) is doing any good). Take care,Steve

4 sticks should be ok, but of course your OC will be limited by the weakest memory chip on any of the 4 sticks.

I suppose somebody with 4GB would have to benchmark, pull out 2GB, and then benchmark again.

Good stuff. Thanks Gary.