What type of upgrade can I do with my 2011 iMac

Hello ivanchu23,

I'm glad you know a lot about computers because it makes this easier for both of us. Even with some research, I believe you can only really upgrade the RAM and hard drive. I say this because the way Apple iMac's are designed, the parts are specifically designed for the iMac and designed to perform a certain way, and do not look like the same card you would buy for a custom PC, meaning you cannot go out and buy a new graphics card if yours was running slow or broke, even if you wanted to. Also, when people make hackintosh's (iMac's made with custom parts), they have to use very specific parts as only certain ones will work with Apple's OS. So, this makes it very hard to upgrade anything in the iMac. If you really wanted an upgrade to your current iMac, I would say go out and buy a higher end 2011 iMac logic board. You can find higher end model logic boards of the 2011 iMac on eBay and other sites if you really want to upgrade. Lastly, I do not know if an external GPU would work. Personally I do not know if they do or do not, but I do not believe Apple supports them considering on their newest Macbook Pro's, there are videos explaining that you have to get a third party application for them to work, and even then, they don't run at their best performance.

Hope this helps!