Nvidia's hotfix addresses issues users have been having with certain 4K panels
There are some growing pains associated with 4K displays, at least for PCs. Quirky issues tend to pop up due to the way the technology works. To run a 4K panel at 60Hz, you need to use a DisplayPort cable, which supports the refresh rate using Multi-Stream Transport (MST). However, this essentially treats a 4K panel as two displays, which introduces weird side effects. A new hotfix from Nvidia is intended to address these issues.
The R337.61 hotfix is a beta download. It's intended to address issues where only half the display or no display at all is shown on Dell's UltraSharp UP3214Q and UP4414Q LCD monitors. It also fixes the Code 43 error message some users have seen after installing 337.50 beta driver on a PC with Hyper-V enabled.
One way to avoid these issues is to use an HDMI cable, but when doing so, the refresh rate tops out at 30Hz. There's a noticeable difference in performance at 30Hz, even just on the desktop -- the mouse cursor is a bit laggy and takes some getting used to.