Phoronix published a review on the With Skylake Out, It's Becoming Easier To Build A Cheap Haswell Xeon Linux System A quote from the article:

Now that Skylake Xeon processors are appearing at major Internet retailers in sufficient quantities (such as the recently reviewed Intel Xeon E3 1245 v5), prices on older-generation Xeon CPUs are falling further. With prices on DDR3, SSDs, and Haswell-compatible motherboards also continuing to fall, it's possible to build a sufficiently powerful yet cheap Haswell Xeon system.

In needing another Linux test system for a Phoronix Test Suite enterprise customer, I opted to do a Haswell Xeon build rather than a Skylake Xeon system. While the Xeon Skylakes are great as shown by my recent E3-1245 v5 Linux benchmarks, they are more expensive and as outlined in that earlier review really require a very modern Linux distribution to play nicely. If using Skylake graphics in particular, a Linux 4.3+ kernel is needed for best support. So in some cases, a Haswell Xeon system still makes sense if wanting to use an older, long-term-supported enterprise Linux distribution and if going after the best value.

 With Skylake Out, It's Becoming Easier To Build A Cheap Haswell Xeon Linux System @ Phoronix