[Pi 4] Cave CV1000 Performance Thread

bbilford83

@dodonpachi Thank you! Just played the first level and it seemed perfect!

dodonpachi

@bbilford83 glad I could help!

bbilford83

@dodonpachi I might as well also ask, I've been messing around with getting the FM Towns Marty emulated on my pi 4 (also a system with a lot of good shmups) and it seems most everything runs like garbage without underclocking the CPU, but doing so has amazingly positive results. But I've been tinkering game-by-game because some games run best with really heavy CPU underclock (like under 40) and some with nearly none. I'm not familiar with whatever list of mame recommendations you found that gave the CPU underclock for Pink Sweets - is there something like that for non-arcade systems I could check to see recommendations for FM Towns? I assume not, but if so, it would be great not to reinvent the wheel...

dodonpachi

@bbilford83 unfortunately, I wouldn't know. The Cave CV1000 games are a unique situation. When Cave developed that series of games, the hardware they used was strategically underpowered so that the game would slow down when there were too many bullets on screen. MAME dev was able to emulate the hardware almost perfectly--the only thing they haven't figured out yet is how to accurately replicate the throttling of the CPU during certain segments of the game. Because Cave's games have a niche following among enthusiasts, they came up with these CPU/blitter values as a sort of workaround for the missing emulation. Not only does it somewhat replicate the slowdown, it has the incidental benefit of making the games more playable on lower end hardware.

bbilford83

@dodonpachi That makes sense. It did seem implausible to me that all mame/fba would have similar info out there but I didn't know the backstory. In any case I did some testing and just posted my results in the thread about fmtmarty. I doubt they're as accurate as these but they got all my games solidly playable.

skykid

Sorry to jump in here. I’m running a Pi4 with overclock set to 1800mhz. I’m using FBneo all the CPU clock and blitter settings as recommended for the emulator here:

https://neo-source.com/index.php?topic=3934.0

I’m not sure how to tweak the GPU as noted by some members in this thread.

The problem is, while the slowdown seems more accurate with the CPU clocking and el_rika’s tenth percent/blitter values, it seems like I’m getting a lot more audio stuttering and big frame drops than people in this thread, and I’m not sure what I’m missing. Someone here noted they only got one instance of audio stuttering in STG4 of Daifukkatsu, but I’ll get instances in the first stage during big explosions where the audio stutters and slows down, and when every end of stage boss blows up and releases medals. It’s really prominent in Akai Katana, stuttering even on the character select screen and during stage 1, from the mid-boss onward.

Can someone give me a hint to try resolving this so I can match the results you guys have achieved here. Should I be using GPU/CPU sync in Retroarch menu? Should I be overclocking the Pi more than 1800mhz?

I’ve tried tinkering with audio latency too, but I find if it goes up too high it actually makes the game itself choppier and everything worse.

Thanks for your help!

Darksavior

@skykid My pi4 is at cpu 2000, gpu 750. I've seen those numbers floating around for years so I kept using them.

I'm not sure if it's a placebo effect or not, but I believe I get slightly better speeds using bullseye/64bit but there's no official way to do that right now.

Also, forget about Akai Katana. It's too slow in certain sections even with the settings I'm using. Maybe the people doing extreme overclocking past 2100 can get better speeds but I'm not doing that.

skykid

@Darksavior

Ah interesting. I didn’t see any other notes on Akai Katana being slow. For me it’s not too slow to play, and responds well for the most part, but I get big drops in certain sections.

Overclock is listed as “extreme” at 1950mhz and “insane” at 2100. I wasn’t sure if I should risk that. I’m using an Argon One case which acts as an entire thermal heat sink enclosure, but I wasn’t sure about pushing it.

EDIT:

Ok I overclocked to 1950mhz and that seems to have brought it up to speed (excuse the pun). Performance is vastly improved and on testing I can’t hear anywhere near the same audio stuttering as before. I didn’t set the GPU but I have a feeling that when the mhz are overclocked in the front end it sets the GPU automatically.

I’ll keep testing but it seems great so far!

sirhenrythe5th

You want max FPS in every situation - try this -> :D

ecto

@skykid I also have a Argon One case and I have my Pi4 overclocked to 2100 MHz without issues.
There is no real risk in overclocking the CPU/GPU as the Pi automatically throttles the frequency when it overheats to more than 80°C.
There are different load tests out there, where all four CPUs of the Pi4 are working at full load. With that you can see if the system stays stable at a temperature lower then 80°C.

... but even then this should be no problem, as in emulation there are seldom all four CPUs used at full capacity at the same time ...

ecto

@sirhenrythe5th Is that yours? :D

sirhenrythe5th

@ecto no, even if i like the idea.
Similar to a calculator with SSD-Harddisk :D

skykid

@ecto Interesting. I mean, when you see the notation for 2100 and it's listed as "you're going to turn the motherboard into candlewax", that's kind of a strong deterrent. Running at 1950 does seem really good, although I might push to 2100 and see how (if) it affects some of the slowdown present on Akai Katana's stage 2 boss.

@sirhenrythe5th Incidentally looks like something out of Ghostbusters.

dodonpachi

@skykid my CPU and GPU have been set to 2100 and 750 since I've had the Pi 4, never had issues. Every board is different, though... hence why they call it the "silicon lottery."

I think my experience with Saidaioujou is somewhat due in part to how I play. If you bomb a healthy amount, you'll clear the screen of bullets, which naturally won't be as demanding performance wise. Hopefully retropie will be supported for the Rock 5B, because that seems like it would run all of these games without issue!

dodonpachi

@barbudreadmon any idea if this will be implemented into fbneo? Seems like we won't need blitter settings anymore, just CPU.

https://github.com/mamedev/mame/pull/10849

barbudreadmon

@dodonpachi See https://neo-source.com/index.php?topic=3934.msg35088#msg35088

dodonpachi

Fbneo was updated to include the new accurate blitter delay function that MAME implemented. I haven't tested it on my Pi 4 yet, but from what I've read, it seems every CV1k game just needs CPU set to 50% now. I'll report back with my personal experience once I have a moment to test them.

https://github.com/libretro/FBNeo/commit/ba134d1c7f1d5bb57be7ec8e4056ad743c27353c