HP 54710A User's Reference Manual page 78

Acquisition Menu
Sampling Rate
When a single-wide plug-in and a two-wide plug-in are both turned on, both
plug-ins sample at the same sample rate up to 2 GSa/s. Above 2 GSa/s, the
single-wide plug-in samples at its maximum sample rate of 2 GSa/s while the
two-wide plug-in samples at the selected sample rate above 2 GSa/s.
Remember, even though you can select a 4-GSa/s sample rate or an 8-GSa/s
sample rate, a single-wide plug-in has a maximum sample rate of 2 GSa/s.
If the two-wide is turned off and the single-wide is turned on, the status line
displays the actual sample rate up to 2 GSa/s. However, the acquisition menu
allows you to select a sample rate up to 4 GSa/s or up to 8 GSa/s. That is
because even though the two-wide plug-in or the four-wide plug-in is turned
off, if it is used as an operand in a waveform math function, it is acquiring
data at the selected sample rate.
Automatic
Automatic lets the oscilloscope select the sampling rate for you. The
advantage is that the oscilloscope selects a sample rate that optimizes the
way the waveform is displayed and the display update rate.
When the record length is set to manual and sample rate is set to automatic,
the oscilloscope selects the highest sample rate that allows all the data in the
waveform record to fill the screen.
Manual
Manual lets you pick a sample rate. However, you have to make the trade-off
decisions on the interaction among sample rate, record length, and
measurement throughput.
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