The first chipset that supported an AMD CPU and ran SLI was the NF4 SLI from Nvidia. Identical to the NF4 Ultra, but was SLI enabled. I don't remember the lane split. I don't remember the name of the first chipset that ran Intel CPUs. Was probably whatever nvidia ran on Intel, might have even been built into Intel chipsets at the time seeing as intel and nvidia didn't have their fight yet.
What makes you ask the question?