The BIOS of these cards has been reflashed so they identify as GeForce GTX 660/650 models but a quick benchmark easily reveals these cards aren't the real deal.
German tech site Heise reports the fake cards entered the German retail channel via distributor Kosatec, who bought the cards in good faith from Dutch graphics card vendor Point of View.
Point of View in turn denies any wrongdoing, claiming they sourced the cards from Chinese manufacturers. The parties involved and NVIDIA are investigating the issue and are planning a recall to ensure anyone who bought one of the fake cards will be able to get a refund.