I have a UH12NS40 that had been cross-flashed to Asus 3.01. I just crossflashed it to WH16NS60 MK 1.03. I tried ripping a Joker 4k UHD disc (which is the trickiest one I have), topping out at 9.5X with LibreDrive 6.02 and speed setting 0=99. However, halfway through it ran into audio sync issues. Attempting this again without the speed setting worked and topped out at 7.8X. This was over USB 3, I'll try this again on SATA with the speed setting and see how it behaves. I may also try USB with a less aggressive speed setting, maybe 0=37 (8.6X).
Edit: 0=85 should have had the same result but didn't. The drive still stopped and started half-way through, did not de-sync audio however, and finished the rip, going back to 9.5X and then slowing down towards the end. This may have been coincidence. More testing with different values.
Edit 2: I think the top speed also determines how aggressively speed is ramped. 0=41 should also top out at 9.5X, but doesn't get there until ~24.5G have been read, at which point it is past the "trouble spot" on this disc, and finishes the rip without ever needing to "stop and start".
Edit 3: Confirmed, 0=70 gets to top speed around 15.5G read and triggers the stop and start issue on this particular disc around 20.5G, never de-syncs audio and gets out of its funk at around 32.5G.
Enough testing. Whether aggressive speed settings are worth it is an individual choice. I think being able to set top speed and ramp independently might be useful. Maybe ramp can be calculated depending on how many speed back-offs due to read errors were encountered, rather than having it be a function of top speed.