Why is the m18x offered with a gtx560m,then sli560m then finaly the powerful gtx580m in sli.but no option for a single gtx580m? Why offer the 580 in sli only? and why is the only single card option a gtx560m,You would think the most powerful pc on earth would have single 580 or amd 69990m,Even the m17x has a 580gtx,and about 4 other pc makers offer 580s in even 15 inchers.I just cant believe an m18x with a huge hi res screen that easily outputs to a big screen or external monitor would offer the 580.I have been scratching my head over this.Sli 580 but only 560 single and the smaller m17 gets a 580?Any reason?Please help me to understand that move some people and some games prefer single gpus,and have less driver and bios it makes no sense to me at all.