Which HS to buy?

[AMDme]

I have the Epox 4PCA3 motherboard. I am going to buy a heatsink for it, my question is which of these 2 are better?

Thermalright SP-94 (the 4PCA3+ will put the heatpipes in to vertical orientation)

Thermalright SLK-947U

No prices, I am getting this HS for free, and have access to machine lapping. What heatsink is the best, no holds barred, after lapping?

 

[dmw16]

I use an AMD, but the thermalright 900 series are supposed to rock. I dont know about the 947U, but if it works as well as the 900U then get that hands down. Also, the Alpha 8492 (I think that is the model) is a good one.
-doug