Dell Precision 7550 dual monitor max resolution @60Hz

@konfilios  It supports up to 3 displays, each of which can be up to 4K 60 Hz.  Intel GPUs have supported that since years before the one built into that system's CPU.  However, while I'm not well versed in Linux, Dell's dock documentation notes that on Linux, the built-in display can't be completely disabled as is possible in Windows and therefore it always counts toward the GPU's 3 display max.  So you may only be able to run 2 external displays, but yes you can certainly run dual QHD displays.  I ran dual QHD displays via daisy chaining from a Mini-DisplayPort output on an XPS 15 9530 from late 2013.