Although Broadwell-based chips are already on the market and Skylake is rumored for next year, Intel's older Haswell microarchitecture is still working its way into new products. The latest is the Xeon E7 v3 series, which is designed for beefy servers with four or more sockets. Known in techie circles as Haswell-EX, this processor has loads of cores, gobs of cache, and a hybrid memory controller that supports both DDR3 and DDR4 memory.
Like the Xeon E5 v3 processor Scott reviewed last year, the E7 is available with up to 18 cores, 36 threads, and 45MB of last-level cache. While the E5 is limited to dual QPI links, the E7 offers three onboard interconnects, allowing it to power systems with a greater number of sockets. Four- and eight-socket systems will probably be the norm, but Intel indicates that the E7 can scale up to 32 sockets in certain configurations.
The old Xeon E7 v2 processor based on Ivy Bridge is capped at 15 cores, 30 threads, and 37.5MB of cache, making the new version a substantial upgrade on multiple fronts. Haswell-EX also brings support for AVX 2.0 and TSX instructions. You may recall that errata prompted Intel to disable TSX functionality in some Haswell and Broadwell parts, including the Xeon E5 v3. That issue seems to have been sorted out, because the E7 product documentation and press release both highlight TSX support.
One of the most intriguing elements of the Xeon E7 v3 processor is its memory controller, which works with both DDR3 and DDR4 memory. We don't have too many details on this component, but Intel says quad-socket systems can support up to 6TB of RAM, while eight-socket rigs can take 12TB. Server builders should appreciate having the flexibility to select the memory type that best fits their needs.
The v3 family is spread across a range of Xeon X7-4400 and E7-8800 variants. The E7-4400 series offers up to 14 cores and 35MB of cache within a 115W thermal envelope, while the top E7-8800 options deliver the full-fat experience within a larger 165W TDP. If you have to ask about pricing, your pockets probably aren't deep enough. The cheapest model starts at over a grand, and the most expensive is nearly $7,200.