This is a rather interesting, and sad move from Intel. They'll be restricting their PCIe lanes to only their highest-end offerings, while offering cut down versions on the others.
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.
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.
http://www.techpowerup.com/204387/i...atures-fewer-pci-express-lanes-after-all.html
I wonder if Intel will be doing something similar with their low-highmid Xeon range, and if so it'll certainly affect people wanting to either build a new Hackintosh, and the new Mac Pro that's now focussing on Dual GPU's, and using the other lanes for Thunderbolt.