Very slow load time

[Ciaran_Zagami]

My PSP's thumb stick broke last week, after some shopping I decided to use an emulator instead of replacing it.

I've only tried two games so far, Persona 3 Portable. Which runs perfectly fine, some slight graphical issues but I assume thats cause the game is being stretched out to a higher resolution

The other game is Metal Gear Solid Peace Walker. And I can't even get past the first loading screen.
I put the ISO in the emulator, hit launch, the game says its reading the memory stick, then it goes to a loading screen. And the load screen never ends. I've been sitting here for 20 minutes now and nothing has happened.

P3P loads in less than 10 seconds. Is this a sign something is wrong with my ISO? Is there anything I can do to improve load time?