It's unsurprising that Dell and HP have announced their upgrades within hours of each other. Intel sets the date when it decides to launches the new chips, and workstation makers can't announce their new models until that embargo has passed - so there's a quick succession of announcements that follow. Expect news from Lenovo, Boston, Boxx and more soon - and who knows, maybe even the Mac Pro will get a much-needed upgrade.
The Xeon E5-2600 v4 chips are based on the Broadwell platform, which is significantly faster than the Haswell platform that last year's v3 chips were based on. The 27 chip varients range in speed from 1.7GHz to 3.5GHz, from 4 cores to 22 and from 15MB of cache to 55MB - though Intel says that one particular model is best for workstations: the 12-core, 3GHz, E5-2687W v4 chip.
By their very nature, creative applications aren't as multi-threaded as server applications - as they're dealing with heavy-duty image processing rather than lots of users. The E5-2687W v4, Intel feels, offers the best mix of speed and number of cores - as procesors with more cores generally have slower clock speeds (the 22-core E5-2699 v4, for example, runs at 2.2GHz).
The v4 chips use the same sockets as the v3 models, so the Dell Precision 5810, 7810, 7910, Rack 7910 and HP Z440, Z640 and Z880 workstations haven't changed beyond the option of having the new chips, faster RAM (2400MHz rather than v3's 2133MHz) and a few other optional extras.
HP is offering a larger M.2 storage drive for its Z workstations. The Z Turbo Drive connects to the motherboard via PCIe, so is up to four times faster than a SSD connected via SATA. You can now get a 1TB version as well as the 256GB and 512GB versions offered previously.
Dell has also announced that its Precision 5810, 7810, 7910 and Rack 7910 can be configured as 'Virtual Reality-ready' systems. These particular builds have the specs to match those recommended by the likes of Oculus for the Rift and HTC for the Vive - but have also been tested with those headsets.