beachballs with external display
Normally I operate my 2010 15" MBP display in clamshell mode with an NEC 2490 external display & for past several months have had many lags (beachballs) when switching apps, websites, etc. When I disconnect the external display and open up the laptop, the beachballs disappear. I assume it is some driver problem with the display but guess it could be operating in clamshell. I've had this arrangement for years & only started having problems several months ago. Any thoughts? I'm on 10.10.2 but think this existed in Mavericks.