If you bought the the cpu retail, you can always stick with the retail HSF for awhile. I'm running at 600 @ 900mhz at only 1.7v, and its running rock stable with the retail. I'm not sure if I want to spend $30 on getting another HSF if I'm only going to gain about 50 - 100 mhz more. So you should try how high you can get the cpu up to with the retail HSF before you go out and invest on an Alpha.
Heifetz