Complex sentence: Current HD DVD drives are not yet able to read regular DVDs at the 12x speed of the current drive; thus slowing down load times and possibly creating incompatibilities with games that gamers would be unlikely to accept.
Split into simpler sentences: Current HD DVD drives are not yet able to read regular DVDs at the 12x speed of the current drive. Thus slowing down load times and possibly creating incompatibilities with games that gamers would be unlikely to accept.