You are welcome !!
So this Custom built did not come with Windows 8.1 or did it and then you reinstalled it recently and then this issue came up with slow restart ?
When showed me Windows update screen definitely not all recommended and important are all done yet, not saying this might be cause.
If setting someone setup in Custom built if reinstalled it should be gone, unless something else not been told about.
Now you said doing safe boot through PC Settings, Advanced options did not work, what happened exactly ?
Strange that cold boot would boot fine and restart take so long. Windows 8.1 fast startup not going have an effect on restarts as was shown as a possible resolution.
When use Event Viewer most recent ones errors in red if left click one and go to the right see an option to Copy, left click it one option will be Copy Details to Text, then open Notepad and paste a few post them here, do one at a time, just save Notepad open notepad and do another.
Just like to see what some of these errors are.
Can be caused by hardware issue or it's drivers as system check these on start, but would figure usually would do it when you cold boot.
Restarts are always bit slower then cold boot.
Have recent driver updates for AMD video card or any other slot cards ?
