XPS 8900, Nvidia GTX 750 Ti, U2414H (single monitor)

I have a Dell XPS 8900 with a Dell U2414H connected to a GeForce 750 Ti (DVI-D 2560x1600, DVI-I 2560x1600, Mini-HDMI 1920x1200) by HDMI, using a Mini-HDMI converter at the video card end.

More often than not, when I switch on the PC, the Dell logo appears, the PC boots, then the screen goes black. If I launch games in full screen mode, the screen goes black. Sometimes when if I get to a login screen for Windows 10, I login, then the screen goes black.

I've updated all the drivers using Windows device manager. All the drivers that I can find via the control panel have also been updated, such as the GeForce experience drivers. The only way that seems to fix this issue, is to switch the monitor off and on again, then most of the time I can see my desktop again. This does not always work with full screen games though. Any ideas on what to check for? I presume the cable is OK. Testing it on other devices without issue.