How much RAM can Windows XP handle?

Hello,
I have been running Windows XP Pro with SP2 ever since it hit the market and in all that time it has never correctly reported the system RAM that I have installed!
I am just in the process of upgrading again and have built the new PC and installed WinXP Pro+SP2. The mainboard is a Gigabyte P35C-DS3R and supports up to 8Gb DDR2 in 4 slots, or up to 4Gb DDR3 in 2 slots. The Processor is a Quad-Core2 Extreme QX6700 2.66GHz, 1066MHz FSB chip and the RAM is 4 x 2Gb PC2 5300 667Mhz DIMMs.
I have opted to load 8Gb of DDR2 and both the POST and the setup table acknowledge the presence of 8,192Mb RAM.
Windows XP Pro+SP2 however reports either 3.50Gb RAM (Control Panel/System) or 4,096Mb Total Physical memory in "System Information ".
I called Microsft yesterday and after hacking my way through the defences that surround their Technical Support people, was told that their is no point in loading any more than 4Gb RAM on any system running XP as it can only actually address a maximum of 4Gb.
(1) Is this true? - and if so why have manufacturers been making boards that will support 8Gb for at least 3 years now?
(2) If it is not true, then why does XP not report installed RAM correctly, and can it use more than it is reporting?
Any help will be very much appreciated
BrianMacMoth

 

I knew it!

Hi Pete,

Yep, I knew it - should have asked the question weeks ago. It will obviously pay me to go back to my 4Gb of DDR2 1066MHz Ballistix and get the whole system running at 1066Mhz.
Many thanks for you help.
BrianMacMoth

 

8Gb RAM???

Hi Pete,

Actually no, quite the reverse! I've got 8Gb that is probably going on eBay tomorrow! But thanks for asking.
Brian