My iMac what starting to become very slow, not Because of CPU limitation but Because The newer XOS versions need more memory and after i installed this memory. Which was very easy with Apple's little guideline, it boosted the speed of my iMac to tremendously, it Felt like I had a new iMac. I have been working with this memory for about a month now and have had not crashes or issues - so perfect value as a local shop had Indicated to me did similar memory sourced through them would be 4X the price.