XP Pro only reads 2.5 Gigs of 4 Gigs

[dop3y]

I know this is probably a dumb question but i am just wondering and would like to know why. I have 4 gigs of memory on my PC. The BIOS reads all 4 gigs but in widows XP Pro it only says i have 2.5 gigs. I would just like to know why that is. Also is XP 64 any different than 32. Is directX10 available in 64?

Thanks and sorry for the dumb questions.

 

[SeasonalEclipse]

You need vista for DX10. As of right now only 64 bit OS's can put to use anyhting over 3GB of ram.. You would need XP 64 or Vista 64 to put use to any extra memory over 3 GBs. Id go for vista 64 depending on the rest of your hardware.

 

[dop3y]

How would i know wether to get Vista or XP 64.
My system specs are:
XFX 780I SLI mobo
Two 8800GT in SLI
E6550 (soon to be either E6850 or E8500)
4G (4 X 1) Crucial Ballistix Memory
300G Maxtor HD
160G Maxtor HD
XP Pro

I play qute a bit of games. Does 64 run slower or not allow you to run certain programs?

 

[Know Nuttin]

If you want to use your 4GB completely, you would go with a 64bit OS. Whether you do vista or XP, it is a preference thing. If you want DX10, you will have to go to Vista. 64bit XP/Vista has compatibility with 32bit programs as well, so your programs should run fine. I believe the only hiccup that I ran into a few years back when testing xp-x64 was antivirus software but that may have been solved by now (I'd be shocked if it wasn't)

As for why you can't see your full 4GB, XP 32 bit can really only address 3.6GB roughly for mapped I/O. Your video card memory also plays into this and seeing as how you have around 1GB of it (8800GT x 2), you are left with around 2.5GB of addressable memory space.

 

[imposter]

I have gone through this before, what motherboard do you have? disable memory remapping function in the bios.

http://www.ocforums.com/showthread.php?t=516013&highlight=4GB

 

[JamesXP]

The thing is you still won't get use off all 4GB, I'd go with Vista64, XP64 has lacking driver supports..