HP’s understandably excited about its new ZBook models. The workstation-class laptops have been refreshed with impressive new hardware — including an optional 3200 x 1800 resolution QHD+ display.According to HP’s press release, it’s only available on the ZBook 15 (so it’s a 15-inch panel). That’s good for a pixel density of 244ppi, which isn’t quite enough to knock the Lenovo Yoga 2 Pro (at 282ppi) off its throne. It’s still pretty darn impressive, though — especially when you consider how long it took OEMs to move beyond 1280 x 800.In addition to the new 15 and 17 inch models, there’s also a more diminutive ZBook for those who crave portability without sacrificing raw power. The ZBook 14 is slim and light enough to fall within Intel’s Ultrabook specifications.All three new ZBook models have been upgraded to Intel Haswell processors. Like all good mobile workstations, there are configurations for both AMD and Nvidia fans — including Kepler GPUs.The ZBook 14 is also available with a touchscreen display — a nice touch if you’re purchasing a new laptop with Windows 8. It’s not available just yet, however. The ZBook 14 will go on sale towards the end of October.And speaking of Windows 8, don’t panic because these new machines are launching just ahead of the Windows 8.1 release. You’ll be able to upgrade all three ZBook models once Microsoft pushes Windows 8.1 via the Windows Store, and it won’t cost you a dime. The upgrade is totally free, and it’s going to deliver a number of very welcome changes — from putting back the start button and a boot-to-desktop option to better multi-monitor options and integrated 3D printing support.