Find out which graphics processor is in use – Apple Support (UK)
Apple iMac NVIDIA MXM 256MB Graphics Card | eBay
Someone gave me this unwanted Mac, anyone know if you can upgrade the graphics cards on these ? Keep seeing conflicting information it's a 24" early 2009 imac : r/mac
iMac Graphics Card Replacement East Midlands Derby – UKSL MacLab
SOLVED: What GPU's are compatible with iMac 27" 2011? - iMac Intel 27" EMC 2429 - iFixit
Graphics card | iRepairs
Adding an external GPU to your Mac is probably a better upgrade option than getting a new one | TechCrunch
2GB Graphics Video Card Upgrade for Apple iMac Mid-2011 27 Inch Core i5 MAC814LL/A MC814 A1312 Desktop All-in-One PC, AMD Mobility Radeon HD 6970M Replacement Repair Parts : Amazon.co.uk: Computers & Accessories