matching h75 fans speeds to gpu temps
This should work if the 290 has a mini 4 pin connector
It would depend if the card and handle the power draw of the two fans. ie, how many watts can the fan slot on the gpu put out. But I would assume that it would something like 5 watts, but take that with a grain of salt because I'm totally just guessing. Take a look at the stock fan, check out it's power draw and try to stay bellow that.