Solution
if it says 'Yes', which means we could deploy the IQ data onto the DRAM of the X410, and the X410 could transmit the IQ data loaded from the DRAM.
and If it's a 'No', which means we'll have to specify the IQ data to be transmitted somewhere from our host PC, and then the X410 will send the signal out for us.
No for DRAM means data always needs to be streamed directly to and from host. If DRAM is available it can be used for both Tx and Rx to buffer IQ data.