I have a laptop (8g ram, iGPU intel HD graphics 5500, dedicated GPU GTX 860M GPU, i7-5500 @ 2.4 GHz w/ 1920x1080 resolution) running windows 10 which I occasionally attach to a second monitor (2560x1440) via an Alienware amplifier (GPU is GTX 960 4gig version) via display port. Attached is an image with more details regarding intel HD graphics.
Using laptop on own - no problems
Attaching second monitor but leaving laptop open - no problems
Attaching second monitor but closing laptop screen - problem
The problem is that things become very choppy on the second monitor. The only situation where second monitor is not choppy is with laptop screen not closed, and display settings in "extended display". If I put it in "second screen only" or close the laptop screen it becomes choppy. By "choppy" I mean EVERYTHING is choppy. Just scrolling on a webpage becomes noticeably difficult. This is a new problem, I've used this setup for about a year without issues, although I have recently upgraded to windows 10 and since then it has been like this.
On trying to troubleshoot, I tried to open the Intel HD graphics control panel and realized I could only open it if the monitors were connected in extended display. Once I changed it to second screen only, I was unable to open it. When I open it in extended display, it only recognized one display which is the "built-in" display at 1920x1080 (i.e. my laptop screen). Windows does recognize I have 2 screens and so does the NVIDIA control panel. I have updated virtually every driver possible, including the NVIDIA GPU, the second screen monitor and Windows 10 updates. I updated the intel HD graphics driver first with intel driver update utility but this didn't help, and then secondly via device manager where it actually seemed to fix things in that I was able to use second screen only without lag, but after restarting the laptop the problem came back. I tried to update the drivers again but it says they are up to date. When I look up the adapters for the second monitor using dxdiag, in extended display it shows BOTH intel HD graphics and GTX 960. In second screen only, it shows ONLY GTX 960.
I would appreciate any help in this. Thanks in advance.
EDIT: attached image
intel pic.PNG 1.2 MB