Complex sentence: AMD Turion is an open platform targeting mobile notebook computer market though little marketing was done on this platform, but it had since compete their mobile CPU technology with Intel to gained more marketshare in this mobile segment.
Split into simpler sentences: AMD Turion is an open platform targeting targetting the mobile notebook computer market. Though little marketing was done on this platform, it has been competing their mobile CPU technology with Intel to gain more marketshare in this mobile segment.