I just looked around a bit. For the 294 it's claimed that high speed mode switches the DAC between a 14bit and a 10bit version. Looks like the 2600 is similar? But it is really hard to find an explanation what this mode actually does.... ISTR (but cannot check ATM) that also the 1600 has a high-speed mode that ZWO recommended not to use... :(

Read More...