difference between 8 and 6 bit panels?

i'm looking at a dell 1704fpt, which i THINK uses a 6 bit, but i'm not sure... but the dell 1705fp uses an 8 bit, which i read is better. Is this true? i don't care about ghosting or whatever, all i care about is reducing eye strains and eye fatigue. will an 8 bit panel be better?

This should answer you questions

http://www.xbitlabs.com/articles/other/display/lcd-guide.html