Ok then, let me run what you're written through my interp-o-tron processor (patent pending). You're asking if you can use parallels (or vmware fusion, or Boot Camp)
to run windows stuff on Mac. yes. I've never heard of nVidia Optimus, but yes, it will use whatever graphics card is in your MacBook Pro, whichever that is. I haven't ever heard of a user-replaceable graphics card for any Mac Laptop. I have heard of an external graphics card you can add to your laptop, but that is, as far as I know, windows only. There is no Mac equivalent. IF you were to run Parallels or whichever software on your Mac, which had a graphics card built in, then you could assume that such software would have Windows capable drivers, and, as such, would take advantage of the graphics card. OS X will run on Macbook Pro and desktop machines just fine. It will have drivers for the graphics card, or the built in integrated card, so naturally, your gaming mileage will vary. yes, you can run Windows in Parallels or vmware fusion, or BootCamp if you so desire. yes, you can switch, but Windows doesn't come preinstalled as a default. As you have found out, you have to do that yourself, partition your Hard drive, etc, etc. Then you can, I think, run Windows or OS X as you wish. Oh, 2 things: I don't think there is a BIOS on Mac, at least not one that's user accessible, and this is a forum for Mac Pro's, not Mac Book Pro's. This is a very common error, Napoleon. Next time, please post your question in the correct forum, or it'll be your Waterloo
JOhn B