Vanilla Demon’s Souls (v1.00) has brutal load times (45+ seconds after death) and item duplication glitches. Update 1.04 (the final patch) reduces load times by 40% and rebalances the game.

: The Blu-ray drive is often the first component to die in a "Fat" or "Slim" PS3. Playing via PKG avoids putting unnecessary wear and tear on the mechanical assembly. Disc Rot and Scratches : Physical copies of Demon’s Souls

The single biggest upgrade is moving from the original 30 FPS cap to a smooth 60 FPS. This is achieved through an emulator patch:

Go to Manage Game Patches and activate the Unlock FPS and Disable Motion Blur patches.

A standard Demon's Souls PKG file gives you the vanilla 2009 console experience, which targets 30 frames per second but frequently drops into the low 20s during chaotic fights (such as the Tower Knight or Phalanx battles).