Your motherboard doesn't officially support anything higher than DDR400, but experience tells me that it will support any Corsair memory you throw at it.
There is no motherboard out there that supports PC4400 (DDR550), so why do Corsair make such a speed? The answer is because Corsair don't want their memory to hold people's overclocking back, i.e. if someone buys VapoChill cooling, which gets your CPU temperature down to -50C, then they want their memory to be able to keep up with any CPU overclocking without overheating (memory heating is passive, you can't buy a fan or watercooling for it).
VapoChill cooling allows people to overclock their P4 3.0GHz CPU by 1GHz, i.e. overclock it to 4GHz, which originally has a multiplier of 15, so to get it to 4GHz the FSB MHz would have to be 266 or ~DDR533, whereas Corsair PC4400 has a DDR rating of 550MHz.
[size=0.5]Full Aluminium ThermalTake Case
AMD Athlon XP 3200+ *400 FSB* Barton (2.2GHz)
ThermalTake Volcano 11+ Xaser Edition Air Cooling
1024MB Corsair TwinX XMS 3200 (Dual Channel 2x512) 2-3-2-6
256Mb XFX 7800 GS EXTREME
2x WD Raptors (10krpm 8MB Cache) 36.7GB using RAID -0
Video Logic SonicXplosion 5.1 Soundcard[/size]