iMac Mid-2010 27 inch (A1312) SSD and RAM disassembly and upgrade - Much FASTER! - YouTube
Amazon.com: 2GB Graphics Card GPU Upgrade Replacement, for Apple iMac 27" 2011 Desktop Computer A1312 Core i7 3.4 MD063LL/A MD063, AMD Radeon HD 6970M GDDR5 2 GBs, MXM VGA Video Board Repair
Install memory in an iMac - Apple Support
How to Upgrade iMac RAM (21.5" and 27" Aluminum): EveryMac.com
iMac Mid-2010 27 inch (A1312) SSD and RAM disassembly and upgrade - Much FASTER! - YouTube
Memory Upgrades for iMac 27-Inch (2012 - Mid 2015)
Amazon.com: 2GB Graphics Video Card Replacement for Apple iMac Mid-2011 27 Inch A1312 Core i7 3.4 MD063LL/A MD063 Desktop PC Computer, ATI Radeon HD 6970 GDDR5 2 GB, New GPU Upgrade Repair
8Gb (2 x 4Gb) DDR3 Memory upgrade for Apple iMac 27" i5 2.7Ghz A1312 Mid 2011 RAM: Amazon.co.uk: Computers & Accessories
4GB/8GB PC3-10600 DDR3 1333MHz iMac Mac Memory / RAM Upgrade for A1278 A1286 A1297 MBP Pro A1311 A1312 27-inch A1347 Mini | Lazada