That article points out it's a different version of the core on the desktop, SP3r2 instead of the SP3 that is landing server side. SP3r2 is only coming with 4 DDR channels.
It's not clear why they're deliberately using a crippled socket here for the desktop. I don't understand the value proposition, and can only envision it driving up motherboard prices. That CPU combined with a crippled socket is surely likely to end up starved of memory IO
Sp3 is for 32-core chips wirh 8-channel memory. Sp3r2 is for 16-core chips with 4-channel memory. The reason the Sp3r2 platform exists is to make motherboards cheaper -- the lines for 8-channel memory force you to use more layers, increasing cost.
They are using the same large socket to reduce time to market -- they had validated the 8-channel socket, they don't currently have a modern 4-channel socket, and they think there is demand.
It's not clear why they're deliberately using a crippled socket here for the desktop. I don't understand the value proposition, and can only envision it driving up motherboard prices. That CPU combined with a crippled socket is surely likely to end up starved of memory IO