I recently installed another GPU on my system. It's of the same type and driver that my other GPU is, and it is PCI whereas the other one is AGP. They are both running and detected, and I am wondering what exactly are the benefits of having two GPU's like this, don't be afraid to get technical. Thanks!
Let me start off with this:
To make use of Dual GPUs they need to be:
Now I've marked part of your text in Bold because you say you have two GPUs, One is PCI and the other is AGP, and while both are recognized by the OS, you're not actually in a true Dual GPU setup, however I figure out that you can run different xservers on them as told here. Or use them for Video editing, or 3D modeling etc.
Still if you don't know what you can do with them, just because you "could" is not a valid reason.
There will be no benefit unless you have an application that is capable of using multiple GPU's. Some possible ways to use multiple GPUs: