Before you start looking at equipment you need to give precise information.
List the clips info, Codec, resolution, frame-rate and so on. List the complete info an the Juice file as well as the sequence.
For the sequence what is the Compression set to. Do a Screen capture of the sequence settings for ease.
Are the clips is a multicam angles or do you have clips on 6 video tracks? How many tracks are viewable at the same time.