I also had the same problem. Use windows build 1511v2 (or any other previous build) or windows 8.1. You can also restore your original windows using recovery dvds or pendrive, if you have any.
Now your display adapter properties will show total 3072 MB dedicated memory combining both primary and linked graphics adapter.
You can use graphics driver version till 17.4.2. If you install above this version then you will again have the same mouse freezing experience.