Playing back some 720p .ts files like Lost episodes 1 & 2 I get noticeable stutter on my machine (P4 2.6GHz, 512mb RAM, Radeon 9700 Pro, NVidia PureVideo codec) whereas on most 1080i .ts and all 1080p WMV files the playback is lovely and smooth. Anyone got any ideas why? Do some of these captures drop frames on the encode or am I lacking some power somewhere when the bitrates climb up. Would more RAM help? Is a 6600GT better at HDTV than the 9700 pro even though the memory bandwidth (which is important apparently) is slightly less? Do ATi have a MPEG2 codec that is up to date and takes more advantage of the Radeon chipsets?