Jack,
What games are you playing... my ps2 games look GREAT. My psone games look a little blocky but still look pretty good.
Did you change the PS2/PSone scaler... I think you can make it none, standard, high.
I have not had a PS2 or PSone game freeze yet. I have completed Twisted Metal Black (maybe like 20 total hours ---several days), all the GTA's work, Burnout, Hot Shots Tennis and Golf, and Devil May Cry 4... along with PSone games such as: hot shots golf, Twisted metal 1-4, family fued, rogue trip, jet moto 1-2, and all the namco games play wonderfully. No freeze at all.
I have the original 60GB and the only time the machine froze was during Saw III Blu ray playback and returned it and replaced that blu ray and it kept freezing... not sure if they ever fixed it... but that is all that has ever frozen.
Let me know more please.