It turns out that our older report suggesting that the most affordable of Intel's new Core i7 "Haswell-E" HEDT processors will feature a slimmer PCI-Express root complex, even if it gives you 6 cores at a [hopefully] sub-$400 price-point, holds true, after all. Intel's wacky approach to its latest HEDT processor lineup was confirmed by leaked manuals of Gigabyte's socket LGA2011-3 motherboards, based on the Intel X99 Express chipset. The manual confirms that while Intel's $500-$750 Core i7-5930K and >$1,000 Core i7-4960X offer bigger 40-lane PCI-Express Gen 3.0 root complexes; the Core i7-5820K features a narrower 28-lane one. This means that multi-GPU configurations on systems running the chip won't be too different from those on LGA1150 "Haswell" platforms.

On motherboards with, say, three PCI-Express 3.0 x16 slots, the i7-5930K and i7-5960X will let you run two slots at full x16 bandwidth, and a third slot at x8. On systems with the i7-5820K, the second slot won't go beyond x8, and the third one will cap out at x4. On boards with four slots, one of them will run out of bandwidth. The trade-off for this narrower PCI-Express interface is the fact that you're getting six "Haswell" cores, twelve logical CPUs enabled with HyperThreading, about 12 MB of L3 cache, and a quad-channel DDR4 memory interface, at a price-point not too far off from the Core i7-4790K. So for enthusiasts with no more than two high-end graphics cards, the i7-5820K could provide an attractive gateway option to Intel's new HEDT platform. You can find the leaked manuals in this thread.