I am wondering whether to buy a 240Hz monitor for my sons to use for gaming. How does fps relate to refresh rate? One has a GTX 750Ti and the other has a GTX 960. Both of them say that they are capable of a 240Hz refresh rate but when they play their games they never seem to get an fps of more than about 170. Does that mean that the graphics card would be able to cause a 240Hz monitor to refresh at 240Hz but that the change in image would actually only occur 170 times per second - a bit like having the monitor sample 240 time per second an image that is changing 170 times per second?
Essentially, does this mean that until they get a graphics card which is capable of an fps that is closer to 240, then a 144Hz monitor would perform in a similar way to a 240Hz monitor?