Is it possible to install two different graphics cards in the same PC?

Hello,

So, to answer your question, yes it's possible to put 2 Graphics Cards on the same Motherboard (as long as it has the ports for it)
However, if your goal is to boost your PC, you might be disappointed...

Indeed, for the 2 GPUs to work together (to get better performance), they need to be the same model from Nvidia in order to create an SLI bridge (unlike AMD's Crossfire which is more tolerant)
In your case, since these 2 GPUs are different, they will work, but independently of each other, so unless you have 2 monitors, there’s no point in adding the second GPU from your old setup.

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Music isn't just listened to, it’s felt.

Hello,

Honestly, I highly recommend against putting 2 GPUs in your PC because it's not the best value for money (better to buy 1 GPU that's a bit more expensive, like a GTX 1660 or even an RTX 2060) because in the end, buying 2 GPUs (which also need to be identical, to avoid compatibility issues) will end up costing you more and you won’t necessarily gain much more power....

Take a look on Amazon, there are some good GPUs at affordable prices right now... (I'm talking about a PNY GeForce RTX 2060 6GB for under 400 euros)...