It's exactly like pairing your existing RAM stick with another one. They'll work together but the slower stick will determine the total memory speed.
If you SLI/Crossfire two cards (preferably same card) you'll have the power of two cards behaving like one better card.
It's exactly like pairing your existing RAM stick with another one. They'll work together but the slower stick will determine the total memory speed.
If you SLI/Crossfire two cards (preferably same card) you'll have the power of two cards behaving like one better card.
Bear in mind that not all cards support SLI/crossfire, and your motherboard also has to support, also your PSU need to be powerful enough to run two GPUs.