Hmm I'm doubting you can run the 5th monitor. Generally having a discreet card more or less disables the mobo VGA output. I guess maybe get 4 monitors and try 3 on GPU, 1 on mobo and if that works you'll be good to go. But remember if you do that and it works, the monitor hooked up on the mobo will basically be a separate entity. It won't benefit from the GPU, and I really don't think you can extend desktop to it. Bear in mind this is just educated guessing... but I don't think it'll work too well.