Working around mobo/OS ram limitations?

[Fred Forsythe]

I recently built a pc based on the Asus P5B Deluxe mobo: http://www.newegg.com/Product/Product.asp?Item=N82E16813131028 Initially, I installed 2 1 gig sticks of Corsair ram: http://www.newegg.com/Product/Product.asp?Item=N82E16820145015. This went so well, I thought what the hey, I'll slap in ANOTHER 2 gigs of the same stuff. Being the Dumb A** that I am however, I didn't BOTHER to read about any possible mobo limitations re: ram. Board's brand new, relatively hi-end, has 4 slots, the 1st 2 sticks worked swimmingly, what could POSSIBLY be wrong with 2 more of the same? Well, according to the mobo manual, "If you install 4 1 gb sticks of memory, the system may detect less than 3 gb of total memory because of address space allocation for other critical functions. This limitation applies to XP 32 bit OS'S which do not support Physical Address Extension mode. For these OS's we recommend installing less than 3 gb of total memory". I read this AFTER I installed the 2 new sticks & saw in control panel/System that I had a total of 2.93 gig of RAM :( Apparently the mobo will support up to 8 gig of ram (4x2) if running Win2k Advanced Server or XP Pro 64 bit. Maybe Vista as well, but this is not mentioned. Other than installing one of these os's, is there any way to get the system to use all 4 gig, or did I just spend $230 for .93 gig of ram? :( :( :(

Thanks,

Fred

[azzey]

The 64-bit version of Vista will take all four gigs happily. It seems that there is lots of confusion about this all over the place!

http://www.brianmadden.com/content/content.asp?ID=69
http://www.overclock.net/windows/77229-windows-xp-ram-limit.html
http://www.geek.com/news/geeknews/2001oct/bch20011002008144.htm
http://support.microsoft.com/kb/555223
http://episteme.arstechnica.com/eve/forums/a/tpc/f/99609816/m/331006081831

The way I understand it is that the physical boundary is 4GB for a 32-bit OS, but various sources state that the maximum for XP is 3GB, and some say it's 4GB. Microsoft lists the maximum supported by XP is 4GB of RAM.

[Fred Forsythe]

Azzey-Thanks for the reply & links. I gather then that XP pro sp2 WILL use 4 gig? I do have a copy of this, which I was planning to install anyway. I see a lot of comments re: the necessity of so much ram, especially in some of the older discussions in the links you provided. I do a bit of fairly large image manipulation in photoshop CS 9, plus a lot of video (use the machine as a multi-media pc), and much multi-tasking. The extra ram should be good at least for the 1st application. Even though this is a pretty new config (core 2 duo) I find it can really slow when doing things like running multiple quickpar's & winrar's, moving large files around, etc. Is the additional ram likely to aid this? I imagine the file moving is affected more by hdd speed. I did run Vista 64 bit beta briefly, it seemed a bit faster, but that's totally anecdotal as I really didn't have much experience with it. Will most all 32 bit applications run under a 64 bit OS? Newegg has the standard 30 day return on ram, maybe I'd be better off spending the $230 on something else re: system speed.

TIA

Fred

[mjc]

Windows XP, like 98 has both a theoretical and a 'real' limit and they aren't the same. Technically 98 had a 4 GB limit, but at 512 MB it went wonky.

32 bit XP has a 4 GB limit, but it reserves the last GB for kernel use (or OS use, depending how you read it). So, yes, you can feed it 4 GB, but it will only let 3 of it be used for programs...

[Fred Forsythe]

MJC-Thanks for the reply, & for clarifying the term "kernel". I had assumed it basically meant system use. I gather that, all things being equal, having 3 gig for applications is still superior to having a total of 2 gig?

Fred

[mjc]

Yeah...it would be.