OmegaFlareX wrote:I'm not using ShmupArch but I have questions about some of the options in the RA latency menu. Hopefully someone here can help me out:
The next two under Hard GPU Sync toggle (Hard GPU Frames, Frame Delay), what are these and how do they affect the input lag? In your video guide they're both set to zero but the tooltip says they could also reduce latency? My computer seems to tolerate 8 or 9 ms of frame delay before weird stuff starts to happen.
What do the Poll Type Behavior settings do? The tooltip here is really vague. I assume "Early" has the least amount of latency?
From what I understand you're supposed to measure the input lag yourself then set the runahead frames to n-1, 2 is generally enough for console cores (NES/MD etc), and having the 2nd instance on removes audio problems. Please correct me if I'm wrong.
Hey man thanks for asking your question.
So those two options in the Latency menu you are talking about are Hard GPU Sync Frames and Frame Delay. I can understand why you would be curious about these settings, as their purpose is ambiguous for sure. So what the Hard GPU Sync Frames does (I am pretty sure) is allows your CPU to run ahead of your GPU to help reduce screen tearing, which is nice. However, this is pretty damn taxing on the CPU so I left it at zero so that people with average gaming computers aren't getting performance problems, as run-ahead is already taxing on the CPU. However, if your computer is a beast, feel free to turn these frames up to reduce screen tearing without any input lag penalty.
So the other option, Frame Delay, is enemy #1 to the purpose of shmuparch. It also reduces screen tearing, but at the cost of adding latency. So, neither of these options improve input lag, but the frame delay option can increase the lag.
Poll type behavior is funky and even I struggle to quite understand how it works in practice. HOWEVER, I did do real time testing of input lag with the different options, and early performed 1 frame of input lag in a real-time test (versus just a frame advance test). So I trust Early as the best setting for Shmuparch.
As far as measuring input lag yourself, yes this is the best practice using the frame advance feature. However, I have already created config files for pretty much all the CAVE, Psikyo, and Raizing shmups, so you don't need to worry about doing that with these games, it's already done.
As for your studdering issue, I have a few ideas that might help. For one, if you have the hard GPU sync frames above 0, that is probably it as that setting is very CPU intensive. If you are still getting stuttering with run-ahead, it could be a matter of your CPU not being powerful enough to smoothly run the feature, as it is very intensive. For example, a Nintendo Switch and PS3 are only able to perform 1 frame of run ahead effectively. Lastly, it may be possible that you are over-running some of your games, and have the setting too high.
Hope this helps!