I`ve been looking for this cpu for a while now. Fortunately it finally came into my possession. Pentium Extreme Edition cpus where first consumer/enthusiast/gamers products with four threads (excluding Xeon cpus of course) because they were based on a Pentium D architecture with Hyper Threading enabled. Additionally at the time of release it was the fastest Intel cpu on sale, the 3,73 GHz clock was an astonishing number compared to upcoming Core2 architecture with only 2,4 GHz speed.
As a nice addon, I`ve got an Intel Bad Axe motherboard with a very nice chipset – Intel D975X dedicated for this central processing unit.