Quang Khoi Thai

Well, I agree they should just start making one double-capacity AC adapter, but it would need to be 600W or 650W. I exceed 500W all the time when benching my M18xR2 with 780M SLI, so that's not enough juice to get the job done. It would be MUCH smarter to just have one monster AC adapter for Clevo and Alienware SLI beasts. You could always have a second 330W AC adapter for travel if you wanted to.

My AW 18 780M SLI almost reaches the limit of 330W when full-loading without OC. I think that there will be higher capacity adapters in near future; and I'm really curious to see how Dell keep the mobility for a 600W adapter

I encountered quite similar problem on my old M17X R4 as yours. The machine turned off suddenly sometimes without a sign. Then I found that the graphic card caused a short-circuit; and that's why the power brick turned off automatically (to protect to system). I removed the graphic card and used Intel HD graphics instead, then machine worked well again.

Thus, I think that your problem comes from the discrete graphic cards.