I don’t know if this is a me thing or it’s a common thing but I have small amounts of lag spikes during boss encounters. I disabled all of my addons that are not essential, disabled my firewall, adjusted my graphics for performance, switched to DX11 and I don’t know what else to do.
edit: if it makes a difference, I do have the new Alternate Full Screen Effects mode on (which I absolutely love and I thank Blizz every day you came out with this as I am epileptic).