That wasn't Intel's plan as recently as 9 months ago....
"Intel Haswell-EX Enterprise Processors To Introduce DDR4 Memory ..."
http://www.techpowerup.com/163592/I...rise-Processors-To-Introduce-DDR4-Memory.html
" Intel to Start DDR4 Usage with Server Platforms in 2014. "
http://www.xbitlabs.com/news/memory...DDR4_Usage_with_Server_Platforms_in_2014.html
Nor 6 months ago... .
" ... After that, the 2015-bound Haswell EP Xeon E5 2600 / 4600 v3 will possess 14 cores, 4-channel DDR4-2133 memory support, quad-QPI links (9.6 GT/s), the works. ... "
Mainstream desktops and mainstream mobile processors are based on the same design. It is not likely Intel is going to decouple them over a year apart.
I certainly can see Haswell-EX sliding out to 2015-2016 timeframe as the Ivy Bridge -EX is only arriving in this year with AMD continuing to implode so there is little to no market pressure to roll out an improvement within a year.
However, even the Anadtech article you referenced has:
" ... . Its just as possible that the box has an unannounced next generation Xeon with a DDR4 controller. But I digress
.
.... The initial target devices will be servers where the improved memory density and power savings are needed most, ..."
http://www.anandtech.com/show/6619/crucial-demonstrates-ddr42133-modules
Ivy Bridge Xeon E5 is being queue up to ship with a very long QA and acceptance process. There should be early engineering samples of the Haswell varaints by now. Or Haswell-EX variants if it is still on track for 2014.
DDR4 has downsides
"DDR4's technical advances come at a price. .....
... That will make DDR4 memory, at least initially, fairly expensive to produce. "
http://arstechnica.com/business/2012/05/ddr4-memory-is-coming-soonmaybe-too-soon/
The much more highly price sensitive mainstream desktop market is probably not where anyone would want to deploy more expensive memory, but higher performing, technology first.