neo 4 question

[med]

i recently got a neo 4 chip installedi n my kids ps2. problem is that out of about 16 back up's(ps 1 games ), only 8 work, most of which only work now and again. i have to keep turning power on / off till they boot . when i try them on a ps1 they all work fine . also a few games are only playing in a few colours. again only on the ps2.
what i'd like to know is anyone else getting same problems with neo 4 or is it just me? should it be playing everything or is it just a neo 4 thing with ps1 games?
i'm burning games on verbatim 80 min cd-r's. maybe its the laser not reading disks too well?
thanks