Upgrading / changing graphics card?

I have an iMac 21.5 "in mid-2011 with an AMD Radeon HD 6750M 512MB graphics card. Because I got the answer in my last question several times that the graphics card is very very very outdated and completely unsuitable for games like Minecraft and Roblox. My even older Macbook Pro 13 "at the end of 2009 with a NVIDIA GeForce 9400M 256MB played these games surprisingly well with up to 200fps) Anyway, I wanted to ask whether the first mentioned graphics card is better than the one from the 2009 MacBook and whether you can use the graphics card iMac can exchange or just equip something and if necessary how high and what should be upgraded. Of course it would be easiest to buy a new PC from 2020. But since that would just be a lot more expensive and I'm still very attached to my iMac, that wouldn't be an option for me.

I hope I have expressed myself clearly and I look forward to your answers.

Yes, the 6750M should actually be much better than the 9400M:

https://gpu.userbenchmark.com/...998vsm7834

Of course, none of them is really good, they are both outdated. But since Minecraft and Roblox are both not particularly graphics intensive, the games should actually run on both devices. Have you ever tried them on the iMac?

You can't replace the graphics card in the iMac, it is soldered.

Okay, first a big thank you for the answer. What about upgrading? Can you allocate more graphics memory to the graphics card?

No, you can't.

Source:

https://forums.macrumors.com/threads/is-it-possible-to-allocate-more-vram-on-gpu.2220213/