The DF88 was the one that surprised me the most, it has 8 DDR channels per CPU for a total of 16. It can run with all slots at DDR2-533, ramps down to six at DDR2-667, and a total of 4 at DDR2-800. These are per channel, so double it if you are looking at the number of DIMMs per board.

The DPK66-S is a Blackford board with 16 FBD slots, another huge number by anyones measure. FBD supports eight DIMMs per channel, but most boards have four. Blackford and Greencreek can do either two or four channels per board. I have no clue if this one is a 2 x 8 or 4 x 4 config, but either way, there are a lot of slots.

It will be interesting to see how this plays out in the market. Intel's position is that FBD allows more expandability at the cost of latency and power. AMD says they can get to the same place with cheaper and cooler DDR2. Until the 667 based FBDs hit with Woodcrest, I would have to agree with AMD on this one. When FBD/667 comes out in a few quarters, the argument turns in favor of Intel unless the board partners can up the limit.
Either way, you have two contrasting solutions for the same net result. The how diverges completely, the what converges completely. Isn't it amazing how things work out? µ