FPS drop on newer builds (0.283 compared to 0.275) with Runahead Single Instance Mode #545
Description
I've been using Runahead with varying degrees of success depending on the game, but I have noticed with the recent MAME build (0.283) there is now a ~5 FPS drop when Runahead single instance is enabled in comparison to an older MAME 0.275 build I had been using.
I suspect this is due to the new audio renderer added to MAME with 0.278 but I wanted to post this here in case it's due to an issue and not just the added overhead of the more accurate audio.
A few notes on my setup:
- RetroArch 1.21.0 Windows 11 x64 - Verified with all default settings
- I've only tested a handful of games so far, all of them are old 1980s vintage so no modern 3D rendering games etc. (atlantis, 4dwarriors, ad2083 are a few examples I noticed it on so far)
- Tested on 2 different PCs, one is a very new PC with a single thread rating of 4925 so I don't think CPU is a bottleneck. Same FPS drop when runahead is enabled.
- Tested on MAME 0.283 31ea352 (cannot reach 60 fps on many games anymore)
- Also tested on MAME 0.275 40edada (stable 60 fps on this version)
- Using Runahead 2nd Instance mode seems to hold 60 fps, only seeing the lower fps in single instance mode. Didn't test preemptive frames much.
Example using 4d warriors - MAME 0.275 frame rate ~ 60 fps
And the same game with MAME 0.283 where frame rate ~ 55-56 fps
Because I also use BFI on my setup the fact that it can't hold a stable 60FPS (or whatever the current game may be) means there is now constant flicker on the screen where the older build was solid with runahead and BFI enabled. Using 2nd instance seems to be a workaround or just turning off runahead.