Help with PSX on PSP!

Alright so I started playing FF8 on my ps3 about a week ago, I am at the second disk now, right in the missile base. I was talking to a guy at gamestop and he stated you could play psx games on psp. So I went home started reading about it, landed on the tutorials in here because they seemed like the best one around.
So I popped the second disk in my laptop, ripped it with Alcohol 52% use the icetea, I already have custom firmware (I believe 5 m-33 6), followed the tutorial and put it in the psp and I got what other people were getting where it was should the POP symbol then go black, and make a pop noise then turn off. Tried a few other things, same thing everytime. So I searched the web more and found another way to use PopstationGUI. Used it worked perfectly played great. For a few mins.
I walked around for maybe 10 minutes in the game, used menus, followed the story, and got to a sort of mid-boss battle. And everything ran fine and fast but then around 3-4 mins in it would just freeze then shut down. This happened twice and I don't wanna try again.
Can anyone help, I don't know what is wrong and I would love to use some of my old games and play them on psp but I can not get it to work and this was the closest I got.