Install graphics card in SUPERMICRO X10SLL-server board?

Question

Video cards

Hello, tell me please. I have a lot of old servers, and the most recent one is E3-1230v3 on a SUPERMICRO X10SLL-F mother. Is it possible to assemble a full-fledged gaming computer for my brother on this platform. Now everything is in the 1st building, but there are also 4 unit buildings - there is no problem with space. Since I myself have not played for over 10 years, I do not understand at all with these PCI E slots. In the description of the mother it is indicated that there is a PCI E 3.0 x8 (in x16) slot, what does this mean? because the video cards are modern that I'm looking at - all under x16? There are 2 small slots on the board itself, and 1 looks full-sized (which is signed as PCI E 3.0 x8 (in x16) tell me what are the nuances. So the piece of iron is not bad, 16 GB fast memory, 4 raptor disks with hardware raid)

Answer 1

This entry means that only 8 PCI-express channels are output to the x16 slot. Not every video card will work, and if it does, then with a reduced performance of the exchange with the RAM.

Answer 2

And tell me, what is the most powerful card? which one will work?