docs: Update TMC_Drivers.md with notes on spreadCycle vs stealthChop modes

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

1 files changed, 14 insertions, 1 deletions

diff --git a/docs/TMC_Drivers.md b/docs/TMC_Drivers.md
index df9dae1f..2f456d4a 100644
--- a/docs/TMC_Drivers.md
+++ b/docs/TMC_Drivers.md
@@ -58,12 +58,25 @@ probing, probe calibration, and similar. The `driver_TPOWERDOWN` and
 `driver_IHOLDDELAY` should also be calibrated accordingly. If unsure,
 prefer to not specify a `hold_current`.
 
-## Enabling "StealthChop" Mode
+## Setting "spreadCycle" vs "stealthChop" Mode
 
 By default, Klipper places the TMC drivers in "spreadCycle" mode. If
 the driver supports "stealthChop" then it can be enabled by adding
 `stealthchop_threshold: 999999` to the TMC config section.
 
+In general, spreadCycle mode provides greater torque and greater
+positional accuracy than stealthChop mode. However, stealthChop mode
+may produce significantly lower audible noise on some printers.
+
+Tests comparing modes have shown an increased "positional lag" of
+around 75% of a full-step during constant velocity moves when using
+stealthChop mode (for example, on a printer with 40mm
+rotation_distance and 200 steps_per_rotation, position deviation of
+constant speed moves increased by ~0.150mm). However, this "delay in
+obtaining the requested position" may not manifest as a significant
+print defect and one may prefer the quieter behavior of stealthChop
+mode.
+
 It is recommended to always use "spreadCycle" mode (by not specifying
 `stealthchop_threshold`) or to always use "stealthChop" mode (by
 setting `stealthchop_threshold` to 999999). Unfortunately, the drivers