This Seeking Tech article compares the two performance modes of The Last of Us Part 1 running on the PlayStation 5 Pro. The footage features most of the prologue from the game. It was recorded off-screen with the Google Pixel 6 camera from an LG B4 OLED.
The new Pro Mode features enhanced rendering and uses PlayStation Spectral Super Resolution (PSSR) to upscale from 1440p to 4K. The target frame rate is 60 frames per second although the cap can be unlocked with Variable Refresh Rate (VRR) and a 120 Hz display.
The regular Performance Mode is rendered at 1440p that is upscaled (without PSSR) to 4K. The target frame rate is also 60 fps although the cap can be removed if you have a 120 Hz display that supports VRR.
You can find the video comparison below (apologies for the grainy footage):
As you can see, both modes can maintain over 60 fps in the prologue. The Performance Mode does have a big advantage over the Pro Mode when it comes to frames per second.
On the other hand, the Pro Mode does appear a little sharper, probably due to PSSR.
The game looks great in either mode. If you want slightly more responsive gameplay, then you may want to go with the Performance Mode. For better graphics, you can try out the Pro Mode instead.