what is dandy
Dandy means "well enough".
Running the games on your system first would be the best way. Unless of course, you are purchasing them (in which case, if they don't run on your pc, it'll be like money down the drain). Why don't you check for the minimum system requirements for the games. If your pc satisfies them just about enough, then you'll be able to run them, but at low settings. If the system satisfies by a fair margin, you'l be able to run them on medium settings. If your system satisfies them by a wide margin ... (you get the drift)