Pure FPS, the best is the card with the highest clocks. That'll be the card with a cooling solution to handle the heat over lesser speed versions. But that rarely ever works out perfectly since many times the card us the wrong color, way over budget, a possible gimmick, noisy as hell etc.
You'll find most ppl will sacrifice the 5 or so fps for a lesser white card to match s blue/white build rather than demand the highest fps and get stuck with a fugly black and red card.