Re: Mint 19.x Cinnamon has been an uncharacteristically rough patch in the road
My T500 has integrated graphics only. (Sure, I may have a fancy, ten-year-old, corporate-discard laptop, but I'm not made of money! ;-) And by the way, more updates have come down the pipeline since I posted, and the lagginess I was experiencing has improved further still, to the point that it's almost not an issue. (Samba still is!) I don't have a clue what specific updates might have been responsible for the improvement. Kernel 4.15.x got bumped up a skosh and a few of my remaining Cinnamon Spices have been updated, but other than that, I'm still too much of a Linux noob to even guess. (Could it be Python? Could Python have something to do with it? ;-)
More on the T500: love the 16:10 aspect-ratio screen; hate that it's the last generation of ThinkPads where you cannot swap the Fn and Ctrl keys in the BIOS. You have no idea how much grief that causes me every time I switch between the T500 and keyboards with a standard layout. Muscle memory is a harsh mistress.