An Introduction to: Understanding SSD Performance

Performance of storage systems such as flash memory cards or SSDs refers to the amount of data that can be transferred in a given amount of time. It is often assumed that performance can be expressed in a single number. Product flyers frequently indicate the performance for a storage product valid under optimal conditions. Understandably, when comparing two products, this one number is generally used as a reference.

However, this is far from sufficient. When examining data transfers more closely, the difference between write and read transfers becomes obvious. Furthermore, the size of the chunks and the randomness of the allocation units (LBAs) in which data is transferred is a relevant factor.

Content

• Write Speed

  • Sequential vs. Random Write Performance

  • Fresh out of the Box

  • SLC Cache

  • Thermal Throttling

  • Example of Write Speed

• Read Speed

  • Sequential and Random Read Performance

  • Sequential and Random Preconditioning

  • Cross-temperature read performance

  • Performance over Lifetime

  • Read Performance and Reliability

  • Example of Read Speed