Pentium III's beyond 1GHz are Tualatins, the 0.13u version of the Pentium III. They probably won't run on your mobo, as they require a bit lower voltage. I *think* (not sure on this) that "fcpga2" refers to the Tualatin socket--which I believe is physically identical to original fcpga but delivers the necessary lower voltage for Tualatins.
Personally, I'd just O/C your current CPU if you want more speed. 733 isn't all that slow, and I believe it can be pushed to 800 or 900. Crashman can probably tell you more....
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