WindowsXPpro Device Manager

I am running XP Pro and in the device manager and system information it shows that I have 2 processors on my machine. My system is a P4 3.0 with hyperthreading 800fsb, Asus P4C800 Deluxe also 800fsb. I have reinstalled the OS a few times and it always states I have 2 P4 3.0 processors. The system seems to run OK but I don’t know why this is or if it is affecting performance or stability.I have the latest bios in my my motherboard and it shows only 1 processor installed. Any ideas would be great.