The number of registered channels does not affect the overall transfer rate of a Time Tagger.
To demonstrate this, we enabled the test signals and aligned them in time. We measured the transfer rate for all Time Taggers models. Until Software version v2.16, the transfer rate for Time Tagger Ultra used to decrease by aligning more than 4 channels, reaching a max transfer rate of 36 MTag/s with 18 channels aligned.
If you experience overflow with Time Tagger Ultra, please double-check your software version. Version 2.17, released in April 2024, has a fix for this issue.