Backups and lens

[bballer]

I have a version 7 PS2 with the no solder mod and swap magic and everytime I try playing my backups most of the backups always lag. But when I play with the originals it works without any problems. This problem is only happening with my dvd backups all the cdr backups work perfectly. I tried the same backups on a friends ps2 and they worked on his. So i was just wondering if there is any way to fix it and if it could be my lens.
Thanks