Hi, thanks for the reply.
Armoury Crate Version 5.0.11.0, no updates seem available
All the points can dragged around and have their positions saved, but it doesn't seem like any of them consistently affect the fan speed, other than the leftmost point, which will always cause a change when adjusted, though not necessarily proportional to the point position.
After some more messing around with the fan curves, this time starting with one of the default curves and adjusting it, I was able to get better behavior, but still not consistent. Note the reported fan speed on the right versus the designed curve on the left.
Here's an example of a fan curve completely not working as expected, the fan speed should be 100% at 62 C, but instead it takes the value of the leftmost point (0%).
Here's another example. The fan speed should still be 100%, but it's not. It's also not 50%, suggesting some kind of calculation error when interpolating the points on the curve.
Strangely, this fan curve seems to produce more normal results, though I haven't the time to test under full load and see if the settings continue to work.
It beginning to seem more like the underlying issue is that the curve interpretation for fan control can't handle steep changes in speed with relation to heat, and the math biases the fan speed low.