Wrong, it does work. You are arguing by changing the definition of "works". Yes, the system will run. Yes, the system will utilize SLI. Yes, it will perform better than a single slower card. It may or may not perform better than the better card alone as that entirely depends on the cards. There are definitely poorly made cards that would benefit from offloading some of that workload. It is extremely unlikely that it would work better than the one better card, but you cannot assume that without stating the cards. Is it worth it? Not at all, cost to performance isn't there. I will give you that. By most, and sometimes all, of the definitions of "works" it absolutely does work. Just because you don't see significant performance gains, does not mean something does not work. It just doesn't meet your needs. Those are two very different things.