Upgrade iMac Intel Core i3 CPU to Core i7 - iFixit Repair Guide
Amazon.com: Timetec 16GB KIT(2x8GB) Compatible for Apple DDR3 1333MHz PC3-10600 CL9 for Mac Book Pro (Early/Late 2011 13/15/17 inch), iMac(Mid 2010, Mid/Late 2011 21.5/27 inch), Mac Mini(Mid 2011) MAC RAM Upgrade :
Original Tested A1311 Motherboard 820-2784-a 631-1335 661-5538 661-5534 For Imac 21.5'' Logic Board Mid 2010 Year - Laptop Lcd Screen - AliExpress
130€ Catalina iMac mid-2010 - 512 G SSD, RAM and CPU upgrades - YouTube
2010 iMac CPU Upgrade - The whole process - YouTube
Will the display of a mid-2010 iMac 27' work when placed in a mid-2011 iMac 27'? - Quora
Upgrade iMac Intel Core i3 CPU to Core i7 - iFixit Repair Guide
Apple iMac 21.5" - Early 2010 Reviews, Pros and Cons | TechSpot