

AFAIK the overall execution speed of the old consoles was always intimately tied to the video refresh rate, not audio. I don’t have much experience programming the SNES specifically, but from what I do know about it and my experience with other retro consoles, I don’t imagine that the sound processor running ever so slightly faster will change the speed of the game overall. Not even to the degree of “less than one second over an entire playthrough” as suggested by the article.
If the oscillator goes far enough out of spec, it may lead to audio glitches and possibly even complete crashes, but I doubt that many games – frankly, any games at all – are busy-waiting on the sound processor as their main way of keeping time.
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OK, I just took a short break. I’ve done a little reading about the potential issue from first sources, and brushed up on the SNES hardware. To reiterate, I still don’t believe that any game will run even one frame faster due to this issue. However, what does seem to be at stake is tool-assisted spreedruns on original hardware. If this oscillator speeds up just a little, but not enough to cause software issues, there’s a chance that controller inputs may be read slightly earlier than otherwise expected (due to the slightly faster audio system finishing earlier), potentially causing a desynchronization with sub-frame accurate hardware input tools, meaning that a TAS may run correctly on one console but not another.
While this is an important issue in the TAS community, I don’t see how this could result in an otherwise “correct” run finishing even one frame faster, as the inputs will still only be read by the game once (or however many times the game normally reads them) per field (“frame”), and the game will still be using the video vertical blank for main timing.
TL;DR: The clock oscillator for the sound chip (separate from the main CPU clock, which does not have this issue) appears to be speeding up over time as it ages. Games from that era use video signal synchronization to regulate their overall speed, so this will not affect game times. It may cause audio glitches or crashes, but it won’t make games run faster. However, it has the potential to cause (and probably has caused) desynchronization issues with tool-assisted speedruns on original hardware.
(I looked into this a bit for another post of this same article.)