Hello... Today I've upgraded my 27" QC 3.1 Ghz 2011 iMac's RAM from 4gb to 8GB. Until now I didn't have any problem. I also didn't use any video, music or photo editing program yet. My question is: Physically old and new RAMs don't look like each other but I can note that specification has changed from 4GB to 8GB in "About This Mac". Existing RAMs are: On the left darker ones... Samsung M471B5673FH0-CH9 1048 2GB 2RX8 PC3 - 10600S-09-10-F2 Newly added RAMs are: On the right lighter ones... Samsung M471B5773DH0-CH9 1108 and 1113 2GB 1RX8 PC3 - 10600S-09-11-B2 What do you think, do they work fine together? Will I have any performance problem or oppositely get any benefit at my video/photo/music editing works? Thanks for your answers.