P5B Deluxe question about running 3 x1gb sticks

I have the following:

*Intel Core 2 Duo E6600 Conroe 2.4GHz 4M shared L2 Cache LGA 775
*ARCTIC COOLING Freezer 7 Pro (cpu fan)/Artic Silver Themal Paste
*ASUS P5B Deluxe/WiFi-AP LGA 775 Intel P965 Express
*Kingston HyperX 2GB (2 x 1GB) 240-Pin DDR2 SDRAM DDR2 800 (PC2 6400) -timing: 4-4-4-12 -voltage: 2.0v -cas latency: 4
*COOLMAX CW-650T EPS12V 650W Aluminum ATX v2.01
*BFG 8800GFX 756 MB OC video card
*Cooler Master Centurion 5

I'm thinking about adding an extra 1gb stick (of the same exact ram I currently have installed) to make my system have up to 3gb total memory. I've heard that running your ram in a ddr config only gives you a slight boost in performance and figure I'd give myself a bit more ram to help run my games. Anyone have any trouble running this mobo with more that 2 sticks of ram? I'm running windows xp, xp can recognize up to 3gb of memory correct?