Defragmentation has No Real Impact on SSDs

Defragmentation has No Real Impact on SSDs

We wish to expose a marketing myth regarding defragmentation of Solid State Drives. The manufacturers of these drives allege that they are so fast that an SSD should never be defragmented because it will reduce the lifespan of an SSD. We ran some scenarios to put some concreteness to these claims and arrived at the following conclusions:

Assumptions:

  1. Documents: Up to 10 files per day, each under 20 MB. Let’s take the upper limit: 10 × 20 MB = 200 MB/day.
  2. Cached Pages: Small HTTP documents, negligible in size, rarely fragment. Even generously, let’s estimate this at 50 MB/day, though likely much smaller.
  • Total data written daily = 200 MB (documents) + 50 MB (cache) = 250 MB/day.

Worst-Case Scenario:

Let’s assume that all 250 MB/day fragments (though realistically, much less would actually fragment):

  • Fragmentation leads to defragmentation that rewrites these 250 MB.

So, the defragmentation-related data written per day = 250 MB × 2 = 500 MB/day.

TBW and Wear Analysis:

Convert to yearly data for perspective:

  • 500 MB/day × 5 days/week × 52 weeks/year = 130,000 MB/year, or 130 GB/year.
  • For a Kingston SSD rated at 600 TBW:
    • 130 GB/year = 0.13 TB/year.
    • Percentage of TBW consumed annually: approx 0.022%

Adjusted Realistic Estimate:

Given the point that both small files (documents) and cached pages rarely fragment, let’s refine the estimate further by reducing fragmentation rates:

  • Assuming only 10% of the 250 MB/day fragments = 25 MB/day fragmented.
  • Defragmentation writes: 25 MB × 2 = 50 MB/day.
  • Over a year: 50 MB/day × 5 days/week × 52 weeks/year = ~13 GB/year.
  • 13 GB/year = 0.013 TB/year, consuming 0.0022% of the 600 TBW annually.

Final Conclusion:

Even with the worst-case scenario (500 MB/day), the impact on SSD lifespan is minimal at just 0.022% annually. The more realistic fragmentation pattern (50 MB/day due to only 10% of data fragmenting) lowers this even further to a negligible 0.0022% per year. This strongly supports the argument: enabling daily defragmentation in Windows 10 would have a virtually insignificant impact on SSD lifespan.

Additionally, the rare instances of large files fragmenting could be worth occasional defragmentation to ensure smoother performance. Let me know if you’d like further clarifications or refinements!

B.A.