The RIP processes a print job in sections called bands. With Dual Band Rendering enabled, it can process the current band and prepare the next band at the same time. It uses additional memory and processor capacity.
This helps deliver print data to the printer more quickly and reduces waiting between bands.

Dual Band Rendering can:
The greatest benefit is seen on systems with multiple processor cores and sufficient memory.
Not necessarily. It is most beneficial when RIP processing is limiting the printer’s speed. It cannot increase the printer’s maximum mechanical speed.
Simple jobs or slower printers may show little difference.