SMR(Shingled Magnetic Recording) is overwriting part of the previously written track analogous to the shingling of a roof.
CMR and SMR each have their Pros and Cons.

How Toshiba SMR helps to maintain random write performance

Toshiba’s innovative Media Cache design, allows the hard drive to efficiently process randomly written data updates to previously written data sets.
New data is temporarily written from DRAM Buffer to the Media Cache.
After merging old data and new data, the revised data is written sequentially to another SMR BAND.
This helps to avoid a decrease in performance when re-writing data, which was previously a downside to SMR.

SMR random writing manner

What is the result of the solution?

PCMark® is an industry standard PC benchmark tool to test the performance of a PC at the system and component level. DT02 Series (SMR 5,400rpm) achieved a higher performance result than Competitor A’s (SMR 7,200rpm).