MBP 15 - 2018 i7 2,2GHz 16GB RAM My problem was : open video in "preview" mode was lagging has hell, the video wasn't fluid and during this time the Touch Bar was just UNUSUABLE. In general all app that need "graphic" like PowerPoint, open a PDF in preview... was lagging...a lot. I fixed it, how I did ? I reset my Mac last night (factory settings), then reinstall the os, clear the SMC, the NVRAM, the problem was still here (bad news). The first "solution" is to force the graphic card to work all the time, "Settings" -> "Battery" -> "automatic switching of graphics" But the Mac is getting hot because of the graphic card, and consume the battery life, it works but it's not ideal.  The second solution (the one works for me) is to go to "setting" -> "monitor" and change the scale, try to see if it's better, if yes, then restart your Mac, and normally you should be fine ! Hope it works for you ! ⚙️

MBP 15 - 2018 i7 2,2GHz 16GB RAM My problem was : open video in "preview" mode was lagging has hell, the video wasn't fluid and during this time the Touch Bar was just UNUSUABLE. In general all app that need "graphic" like PowerPoint, open a PDF in preview... was lagging...a lot. I fixed it, how I did ? I reset my Mac last night (factory settings), then reinstall the os, clear the SMC, the NVRAM, the problem was still here (bad news). The first "solution" is to force the graphic card to work all the time, "Settings" -> "Battery" -> "automatic switching of graphics" But the Mac is getting hot because of the graphic card, and consume the battery life, it works but it's not ideal.  The second solution (the one works for me) is to go to "setting" -> "monitor" and change the scale, try to see if it's better, if yes, then restart your Mac, and normally you should be fine ! Hope it works for you ! ⚙️