Yeesh... I posted this comment yesterday, but my username was considered 'inappropriate' by the moderator(s) because it contained the 4-letter "P" word that my 2 year old uses to describe a stinky mess in his diaper. My account and comment were deleted as a result. That seems a trifle absurd to me, but I'll play by the rules in order to try and be helpful.
Anyway... your original post says that you have the latest bios on your motherboard.
My question: did you personally flash the bios on the motherboard after purchasing the machine? If so, did the sluggish-ness start happening AFTER you updated the bios?
If you answered YES to both of the above, then the problem might be that the bios update has resulted in a drastic UNDERclocking of your CPU. This happened to me last week with my Athlon XP 2500+. I flashed the mobo bios, and noticed a sharp drop off in game performance and 3dmark03 score. What had happened was the the bios update caused the CPU and front-side-bus frequencies to be set VERY low. My processor should be clocked at 1.8GHz, but was only being run at 500MHz.
After I fixed that, everything was grand.
-Ninja