I just purchased a Sony BWU-500S blu ray burner. I burned about 10 HD MKV clips to standard blu ray 25Gig. All Burned successfully, but when I play them back from the drive I get laggy video, and audio. Freezing in parts, skipping audio, and sometimes the video goes into slow motion. I can play everyone of these files fine on my hardrive in every program that plays mkv files. So that basically eliminates the pc not being fast enough etc. So im leaning toward the Sony drive just not being fast enough to read what it wrote?? I can copy them back from the burned blu ray disc to the hard drive, and play them flawless. Any ideas what could be the problem I using 64 bit windows 7. Also Ive checked my media compatibility with the drive, and there supported. Should i just return the drive?