I just purchased 8g ram (2x4g) 1066mhz for my iMac 2.93mhz 2010 model. In my haste to take advantage of a special, I didn't realize it was 1066mhz forgetting that my iMac currently has 1333mhz (2x2g) installed. My question is: Can I install the 1066mhz along with the 1333mhz without there being a conflict? Or should I just return the 1066mhz chips and get (2x4g) 1333mhz to keep all the modules the same? Also: If there is no problem with using both at the same time, will the difference in speed be a noticeable drop in performance compared to having all the modules at 1333mhz vs. 1066mhz? I am guessing the 1333mhz will drop down to 1066mhz, but I'm just guessing.