Interesting. You probably want to start with one card and run that for a few games, make sure drivers are good, no hiccups. Then, go SLI with 2 cars, and run that, do some testing to make sure your system and the benchmarks show everything is as planned and record these scores too so you know how 3-way SLI helps (or maybe not) your system. Then, go for the 3-way (get ready for some noise) and run furmark! Wouldn't be a bad idea to put the extra heat output to use by toasting a few marshmallows while furmarks checks the stability of your system. Seriously, if you're gonna go 3-way SLI, make sure you have excellent airflow. BTW, which cards are they and what is your PSU?