32bit OS need mobo that supports 4g+ Help

Hello guys, quick newbie question, i have a budget build set up, and with this build i plan to run on a 32bit win xp OS, the asus p5q mobo i plan to get states that 32bit OS may only read 3g of ram. Is this how it is with all mobo's on 32bit ? If not, can anybody tell me a mobo that will indefinitely support 4g on a 32bit OS that is in the performance range of this p5q? I dont want to waste 1g cause of this. Thanks ahead of time guys !... Here's the Setup if you are curious :

Psu - OCZ GameXStream 600W SLI ATX 12V Ver 2.2 Power Supply (Retail Box) $94.99 ($30.00 CAD Mail in Rebate)

Hard Drive - 500GB Seagate Barracuda 7200.11 SATAII-300 7200RPM 32Mb OEM $79.99

Gpu - Asus® Radeon EAH4850/HTDI/512M - Radeon™ HD4850 VPU w/ 512Mb DDR3& PCI Express 2.0 (Retail Box) $214.99 ($30.00 usd Mail in Rebate)

Cpu - Intel® Core™2 Duo E8400, 3.00-GHz @ 1333Mhz w/ 6Mb Cache (Socket 775) (Retail Box) w/ Heat Sink & Fan $179.99

Ram - OCZ 4Gb PC2-6400 DDR2 Dual Channel Reaper CL4 HPC Edition (OCZ2RPR800C44GK) $114.99 ($30.00 CAD Mail in Rebate)

Mobo - Asus® P5Q , Socket 775, Intel® P45Chipset w/ PCI Express x16 (ATX) $134.99

Case - Antec® Nine Hundred Ultimate Gamer Case, Black $109.99