Chosen Solution
Can I use i7 3770s to upgrade iMac 21,5" Late 2013 instead of i7 4770S
First there was no 3770s 2013 21.5 iMac. There was a 2012 system which was just a 3.4GHz I7-3770 as you can see here iMac13,2 and here’s the 2013 systems iMac14,3 which does have a I7-4770S. So where does that leave us? Not sure why you are down grading your system CPU. If we compare the performance of these two CPU’s the I7-4770S is the better CPU and the 2013 system also offers the better GPU
