I recently purchased the great 15" refurb MBP in the signature. I noticed that I was getting some black "dots" that appear in the finder window when I click on an icon. These dots are only within the open finder window and change their location and pattern randomly. I finally localized the problem through gfxcardstatus in that it does not occur when using integrated graphics. It seems logical that it is an issue with the discrete card but the issue does not extend to other programs (youtube videos are affected). Other programs look perfect on discrete. I wondered if anyone was familiar with these or had a suggestion or way to test the card.