Might be a heat issue. The case is well ventilated, and has more than it's share of fans, (top, side, rear, hard drive, CPU (obviously), etc.) but as mentioned, if an unused card if hot to the touch, some serious heat is being generated. A liquid cooled system wouldn't work because, well, with three cards sandwiched into one another where would the cooling blocks go? How exactly do people run three or four powerful cards at once without the heat being a factor? There is a way to do it...I'm just not sure what it is.