Review on CT2K4G3S1339M - Crucial 8GB Kit (2x4GB) DDR3 1333 MHz CL9 Memory for Mac, Enhanced SEO by Robert Castro

iMac 21.5 inch Mid 2010 3.2GHz Intel Core i3OS X Yosemite 10.10.1 Wanted to upgrade the 4GB RAM provided by Apple. In search of the best performance. Interesting installation problem. First try: The original two 2GB DIMMs were in BANK 0/DIMM1 and BANK 1/DIMM1. Added new Crucial 4GB DIMMs to open slots for BANK 0/DIMM0 and BANK 1/DIMM0. The iMac made a warning beep when it started up. Annoying noise. I had to turn off the device by holding down the power button. Attempt Two: Swapped one in each of the two sets so the DIMMs were in the same banks. Another beep at startup. Switch off . . .Three attempts: Loaded only two new 4GB DIMMs in BANK 0/DIMM1 and BANK 1/DIMM1. Booted up well. "About this Mac" showed 8GB of RAM. Success with the new Crucial RAM. Fourth try. With two new Crucial 4GB DIMMs in BANK 0/DIMM1 and BANK 1/DIMM1, load two original 2GB DIMMs in bank DIMM0. loaded. worked fine "About This Mac" showed 12 GB of total RAM. It was the intended end goal. Success with both old Apple/Samsung RAM and new Crucial RAM. It's strange that the old RAM had to be moved to open slots. The specifications of the old and the new match, DDR3 1333 MHz. Always had success with Crucial RAM on PC and Mac. I will continue to recommend Crucial. Hope this helps other DIYers.