The European TV standard (PAL)50Hz and the US/Japanese standard (NTSC)60Hz run at different speeds - certainly where DVD is concerned. For example, a film lasting 120 minutes at the cinema will last approx 5 minutes less when converted to PAL DVD. NTSC DVD runs at the correct speed but you get a bit less clarity (Fewer horizontal lines in the image). This is why, when I buy a DVD I try to get an NTSC vers. Music plays at the correct speed and of course so does dialogue. Voices will sound noticeably lower & slower when comparing a PAL & NTSC vers of the same DVD. With Bluray this SHOULDN'T happen as all HDTV's are capable of running at 60Hz and they should all play at the correct speed - unless it's a lazy or very early conversion. The details on Amazon aren't always correct though, so the UK vers may well run at the same speed and have the same running time. Hope this answers your question.