Data processing method for controlling write speed of memory device to avoid significant write delay and data storage device utilizing the same

A data processing method for a data storage device comprising a memory device and a memory controller, wherein the memory device comprises a plurality of memory blocks and the memory blocks comprising a plurality of spare blocks, and the data processing method comprises:

• obtaining a number of spare blocks corresponding to a first operation period;
• determining a write speed compensation value according to the number of spare blocks;
• determining a target write speed according to the write speed compensation value and a balance speed;
• determining a target garbage collection speed according to the target write speed;
• processing one or more write commands received from a host device in the first operation period according to the target write speed;
• and
• performing at least one garbage collection operation in the first operation period according to the target garbage collection speed.

A data storage device, coupled to a host device, comprising:

• a flash memory device, comprising a plurality memory blocks, wherein the memory blocks comprises a plurality of spare blocks;
• and
• a memory controller, coupled to the flash memory device and configured to access the flash memory device, wherein the memory controller is configured to obtain a number of spare blocks corresponding to an operation period, determine a write speed compensation value according to the number of spare blocks, determine a target write speed according to the write speed compensation value and a balance speed, and determine a target garbage collection speed according to the target write speed,
• wherein the memory controller is further configured to process one or more write commands received from the host device in the operation period according to the target write speed and perform at least one garbage collection operation in the operation period according to the target garbage collection speed.