Not sure if this is in the right thread, but here goes.

I just built me dream system (darn near) and im almost 100% happy. i got the new XFX 780i SLI mobo, intel Q6600 BFG 8800GT PCIe 2.0, Ultra Chil TEC CPU cooler (my pride and joy of thie system) and 4GB of Corsair XMS2 DHX memory. my issue lies in Windows Vista and the Memory.

When installed, i placed the memory in the correct DIMM slots, 2&3 like the manual says, and start windows just fine, but in vista, the performance monitor or whatever its called shows only 2.5GB. when the systems POSTs it says i have all 4GB 4,128,###. so i know the memory works. i even swapped the sticks so A & B sticks were in slot 2&3 and then visa-versa just to test the slots... but i dont know.

the Ultra Chill TEC cooler is so big, i can only place the sticks in slots 2&3 instead of 0&1 ;_;

I updated the BIOS and reflashed it already, and im still only getting 2.5GB.. i know windows vista 32bit only recognizes 3.2GB total, and im fine with that for now. but wth is going on.

Try looking for something to do with remapping in the bios.

how would i "remap" the bios? ive never heared of that >_>

some memory is also taken up by the graphics card.. Not sure how much or if its dynamic, but in mine, it shows 3.3GB.. Maybe u have allocated some ram for vid in bios?? As to "remapping", there is a feature in the bios.. In mine, P5KC, its under "northbridge chipset configuration".. Its labelled as "memory remap feature"... Enable it and give it a try..

Windows x86 will not simply recognise 3.2GB every time

It depends how much memory is mapped.

I've seen a system with 4GB of Ram, nforce 680i board, 8800GTX SLi, physx card, only see 2.5GB.

There isn't much you can do about it, it seems your system has alot of mapped memory.

Use x64. Or server 2003 sp2 x86, if you reeeeally want a 32bit OS.

Are you sure that it's just only using 2.5 GB at the time? "Performance Monitoring"

I have never used Vista (i still love XP to death) but it seems like its the same deal with the boot.ini and 32-bit OS. Open up your boot.ini file and add the /PAE switch to the lines of code there. That should tell your system to add a "physical address extension" to your memory so if it didnt already use the 4 gigs installed, it will use as much as the OS can recognize and allocate the rest for kernal useage.

u didnt say which graphics card u using, n hw much memory they have i total.

coz ull need to reduce it from ur ram that os can see.

just google. n ull find 10 question like yours.

the Graphics card is the BGF 8800GT. i did say that >_> but. i have googled "Windows Vista Memory" and "Windows Vista 2.5 GB" and all kinds of stuff and all i get is adds and reviews. google aint what it used to be /cry

PAE switch has been disabled since SP2 and no longer does anything

BIOS remap feature will only resolve issue if the bios doesnt detect all 4gb, which it is already detecting all ram so this will not resolve the issue either.

In 32bit OS's there is a 4gb limit on physical addressing space. As there needs to be memory addressing for your GPU ram and other devices (sound cards, raid cards etc.) this 4gb limit cuts down. 512mb from the gpu would bring you to a 3.5gb limit then with other addressing on top of this you could well come down to ~2.5-3.5gb addressing space left for your RAM. Although 2.5gb seems a little low it is very possible. To get around this i would move to a 64bit OS or as suggested Server2003 SP2 supports more addressing space also.

Exactly.

Over 2GB, use x64.

x64 is now stable and reliable, and no new modern build (with new modern hardware) will encounter driver issues.

If you really want x86, your only option is Sever 2003 patched with Service pack 2.

To go beyond 4G you need to use a 64bit OS...

I'm using Vista Ultimate 64 Bit with 4G of memory... No issues

I'm actually in PAE mode on my XP SP2. It says so in system properties.

looks like im gonna have to dump $400+ more into vista 64bit.... this aint right.

You could get it for $7.00

7? where and how long would i be in jail for?

You don't have to go to jail at all. If you have a retail version of Vista-32, Microsoft will ship you a Vista-64 DVD for a small fee. It comes to about $10 with S&H. It uses the same activation key as your old 32-bit DVD. Here's the URL for more info:

http://www.microsoft.com/windowsvi [...] fault.mspx

I don't think it applies to OEM versions, but you can try.

Thers another way to get it from MS for $7.00. You go threw the upgrade page add a upgrade and make sure to click you dont have the disk. Then it puts the upgrade in your card and a disk in your cart. The disk is free the upgrade costs. Edit cart and remove upgrade, you still get the disk for $7.00 shipping. Install it then you have 30 days to try it out, and dont forget the rearm feature that gives you 120 days to try. After the trial you will need to activate it and there is a couple of options there.