Slowdown on PS1 games

Ka

@windg I don't have access to the PAL version of GT2 unfortunately, but I did try running the game at 1280x720, and the slowdown was still present - the in-game timer was about thirty seconds behind the stopwatch after a three minute race.

Presumably it's not down to the game overtaxing the Pi, then...

dankcushions

@Ka one thing you could try is raising
the CPU speed core option. there’s some info on this here: https://retropie.org.uk/docs/Playstation-1/#performance-psx-cpu-clock

Ka

@dankcushions Thanks - will give that a shot. Daft question from me - should I be raising that figure or lowering it? What does that figure actually do? Presumably I can fiddle around with it in-game without breaking anything.

The documentation says "The clock speed percentage of the emulated PSX hardware's CPU can be adjusted by the user" through this option, and that the default is 57.

That sounds like the emulator defaults to 57% speed of the emulated PSX CPU - is that right? It sounds odd to me. Were PSX CPUs underclocked?

dankcushions

@Ka raising, like i said :) i don’t know where the 57 figure comes from or the logic behind it, but that is the figure that seems to be most compatible across all games. if you set it to 100 you’ll get issues i expect, so be sure to set the config per-game as per the link.

Ka

@dankcushions OK, cool - much appreciated. I'll give that a try.

Ka

@dankcushions said in Slowdown on PS1 games:

@Ka one thing you could try is raising
the CPU speed core option. there’s some info on this here: https://retropie.org.uk/docs/Playstation-1/#performance-psx-cpu-clock

This was a really good call, as it made a HUGE diffference. Wipeout and Rage Racer appear to run at full speed with the CPU clock jacked up to about 70. I pushed it up to 95 at one point, with no apparent ill effects - my trusty stopwatch seemed to indicate that the game was running at the right speed and wasn’t going too fast, and there was no slowdown that I could see.

With Gran Turismo 2, even at 95% there was a tiny bit of slowdown - about two or three seconds over the course of a three minute race, but I couldn’t honestly say that this wasn’t present on original hardware and it’s hard to see how you would notice when actually playing the game and not scrutinising it for speed drops.

So thanks - I can finally play those games properly again!

windg

I have complete GT2 and i didn't understand that was slow(my bad), until i set the CPU to 95. Now is running smoother and better. Nice discovery Ka, thanks! Thanks dankcushions too for the suggestion, i will try it with others games that looks slow.

SgtJimmyRustles

@Rion Question, what special about that bios?

Darksavior

@dankcushions Have you guys considered putting PSX Beetle in the experimental section for the pi4? It's usable, when overclocked (because the dynarec is too unstable), on protected 2d games that Rearmed can't run.

Rion

@SgtJimmyRustles said in Slowdown on PS1 games:

@Rion Question, what special about that bios?

psxonpsp660.bin is a BIOS dumped from the PSP's PlayStation emulator. It is said to improve performance for certain PlayStation games as is a streamlined version of the BIOS, lacking irrelevant features like the built-in CD Player and Memory Card manager.

Darksavior

@Rion Is there any evidence to that? I tried it in psx beetle and gained zero fps.

Rion

@Darksavior PSX BIOS from PSP 6.60 optimised to play games more smoothly: but how?

Darksavior

@Rion I would've liked video evidence, but o well. I don't see it.