Just wanted to share my experiences using an old Core i5 Lenovo Thinkpad X230, running Linux Mint, with Ardour and Qjackctl.
I noticed I was getting Xruns if there was anything “happening” on the screen, a good example being meter monitoring on Ardour, or tracks scrolling across the screen. Or even using the mouse to move a window. If I chose to have something “static” on the screen - say Qjackctl patch window full screen - sound would be pretty much perfect, no xruns.
So - clearly something graphics related. I’d followed all the usual kernel tuning suggestions - real time kernel, cpu performance mode, unlimited etc etc… with no joy. And I’d done a lot of more low-level reading about “shared IRQs” but couldn’t find any evidence that this was the cause.
Eventually - it dawned on me that these Thinkpads are great, robust, powerful little laptops but are designed for the business world so usually have puny little graphics cards in them.
So I switched my desktop from Cinnamon to Mate. Problem solved - no more xruns, no matter what I have dancing around on the screen. And, with a bit of theme-adjustment - it looks just as pretty as Cinnamon, if not better.
I hope this helps someone out there?
Sput