I don’t know how to check network cards. I figure if i bought a card that will run 100mbs and the other has a built in card at 100 mbs it would default to 100mbs. Yes its on wireless right now. No cat 4 anywhere. Logging into the Router shows it set at at least 150mbs.
just to get this straight, you have 2 computers, both have wireless adapters, and you are using a random router to get them talking to each other.
Wireless cards are super annoying, and the range vs speed curve is usually very bad.
in any case the software that came with your cards will usually show the speed that it is connected at and you should have a little signal bar thing in the corner near the clock.
realistically as other people have said, get a thumbdrive and use sneakernet
If one card is hard set for 100/full, and the other is set for auto/auto (or 100/auto, or auto/full), it can cause issues as well. both should be set the same.