Haswell-E is a Tock revision in Intel's roadmap, meaning that it a major architecture revision on an unchanged lithography. Major criticisms of Ivy Bridge-E were down to that platforms status as a Tock revision, making it essentially a die shrink and cleanup of Sandy Bridge-E but with few new features and in this case no new accompanying chipset.
The new CPU features significantly more transistors than both IvyBridge-E and the behemoth SandyBridge-E of the past - 2.6bn compared with 1.86bn and 2.2bn respectively. The die size is also commensurately larger - 355.52mm^2 against only 256.6mm^2 for Ivy Bridge-E. Nonetheless Intel still eschew an integrated GPU on this part, determining that such solutions are unnecessary for the HED market.
The i7-5960X Extreme Edition is unique in the Haswell-E range in that is incorporates a full 20MB L3 Cache, shared between the eight CPU cores. Even were it not for the two additional cores this would have a tangible benefit in a wide variety of repetitive and threaded tasks, whilst the cores themselves put the CPU further over the top. It appears that Intel have had to rein in the CPU a little in fact, making use of only modest 3GHz base clocks; however you can be sure that enthusiasts will find pushing those limits immediately. By comparison the Tubro Mode is quite aggressive, hitting 3.5GHz under optimum conditions.
Headline features therefore are a large step above the IvyBridge Core i7-4960X, but it's worth noting that the features listed above are only part of the equation. Thanks to a chipset revision the Haswell-E platform brings with it more benefits than simply two more cores and DDR4 RAM; compatible X99 motherboards also bring support for Thunderbolt 2.0, up to five discrete GPUs in 5 x 8 lane Gen 3 PCIe 3.0 configuration, and 10 SATA3 6Gbps ports.
Motherboard manufacturers have also striven to keep their X99 designs in pace with the recent Z97 updates. By this we mean that many have included support for next generation storage interfaces either through M.2, SATA Express, or both. It's our understanding that this isn't a core feature of the chipset, but nonetheless it's a welcome addition and will hopefully encourage designers of these devices to increase the pace of release.
The specs of each CPU in Intel's professional/enthusiast-grade product stack make it clear where they each line up.
Intel suggest that this CPU improves performance in suitable tasks by as much as 32% versus the previous Extreme Edition. To place that into some sort of context the leap from Nehelem (X58) to Sandy Bridge-E was of this order of magnitude and hailed as a monumental leap forward. We shall see if Intel's claims bear up to scrutiny.