The computer comes with an AMD Radeon HD 6770M 512 MB discrete graphics card. According to this, the earliest iMac to support 4k is Late 2013. By then, I believe iMacs were using GeForce cards and I'm also not sure they're actually physically discrete, so I'm not sure I could just swap out the card for one in a later Mac. However, it also seems that there are firmware blocks on using non-mac GPUs in a Mac. Is there a way around this? I basically got a 2011 iMac for free and I want to use it at 4k with the monitor I already have.