
I love Fallout and I love my Playstations, but play Fallout on literally anything else and you'll have a much better time. It's just plain poorly programmed on an underpowered platform. I also gave myself the the Cheat Terminal so I could avoid picking up anything and I avoided bumping into anything so it's saved place wouldn't change. I removed the weather effects, trash on the ground, dust/particle effects, useless items, etc.

My PS3 is on Custom Firmware so I installed a bunch of PC mods (yes, they work natively), to see if I could improve how it runs. I've done a lot of testing on these games because I love them and really wanted to enjoy them on my PS3, I don't have a gaming PC. Wait till the HDD light stops blinking (around 20 mins depending on your HDD). One thing that can help is to start your game and then pause it or go into your PipBoy, the game does a background install, so this will allow it to write everything all in one shot and allow for gameplay without simultaneously trying to install. After a certain size the game is unplayable.

You'll want to save often due to the random freezing, but the more you save, the bigger your save file gets. Mainly it's the GOTY editions, the vanilla versions perform better but still not very well. It's bad, it will affect your enjoyment of the game.
