Trancemission

Hi, I'm new to the forums. I'm looking for more information on Alienware m17x r3 with a specific upgrade to the gtx 980m as well. According to google search, the Alienware m17x r3 does have optimus capabilities inside bios options so does that mean an upgrade to the gtx 980m mxm card provided for Clevo will work? If it does indeed work, does anyone know if the cooling solution for stock nvidia gtx 460m will work with gtx 980m to cool it? OR Do I need to buy more cooling/thermal pads OR Do I just plainly need to get a new gtx 980m cooling kit?