Here's my limited understanding. The non-Pro version of the camera streams the readout data directly to the USB bus. This has some problems:
1) If there is an error in the stream, the image is lost. USB protocol does not allow for error correction and even if it did, once the readout data is sent to the bus, it is lost forever, so data could be re-sent.
2) The USB traffic has to be set such that errors in the stream are minimized.
3) The slower the USB speed, the longer the readout process takes, which increases amp glow.
Number 3 in particular relates to the OP's question. The amount of amp glow experienced will be directly related to the USB traffic setting. With the on-board DDR memory, the camera can read the sensor at very high speed directly to the DDR memory, which will minimize amp glow. This also has big advantages for transferring the image to the PC. Since the transfer speed is now unrelated to the readout speed, and the image is safely stored in DDR memory, it can be send to the PC over USB at any speed and the chances of a lost frame are pretty much non-existent. This is also an advantage for those who find USB2 to be more reliable than USB3. Since the amp glow is not related to USB speed, either protocol can be used without detrimental effect.
Edited by spokeshave, 18 July 2019 - 06:26 AM.