{"id":"external-drives.why-does-the-speed-test-give-different-results","url":"/faq/external-drives/why-does-the-speed-test-give-different-results","category":{"id":"external-drives","title":"External drives"},"subcategory":{"id":"speed-and-hardware","title":"Speed, cables and hardware"},"question":"Why does the drive speed test give different results each time?","alt_questions":["Benchmark results vary","Speed test slower the second time","Inconsistent read write speeds external SSD","drive benchmark numbers change","Why is my SSD slower than advertised?","Speed test lower than the box says"],"short_answer":"Speeds vary with how full and warm the drive is, other activity on it such as Spotlight, and the port and cable. Makers quote best-case numbers. Close other apps, connect directly and run the test twice for a fair reading.","answer_markdown":"Real drives don't run at one fixed speed. Results shift with how full the drive is, how warm it is, whether something else is reading or writing to it at the same moment (Spotlight indexing, a backup, an open app), and the port, hub and cable in use. Drive makers usually quote best-case figures, so everyday results are often lower.\n\nFor a fair comparison, close apps using the drive, connect it directly with a good cable and run **Run benchmark** a couple of times. Storage Studio's verdict cares about whether the drive is comfortably fast enough, not about small differences between runs.","answer_html":"

Real drives don't run at one fixed speed. Results shift with how full the drive is, how warm it is, whether something else is reading or writing to it at the same moment (Spotlight indexing, a backup, an open app), and the port, hub and cable in use. Drive makers usually quote best-case figures, so everyday results are often lower.

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For a fair comparison, close apps using the drive, connect it directly with a good cable and run Run benchmark a couple of times. Storage Studio's verdict cares about whether the drive is comfortably fast enough, not about small differences between runs.

","answer_text":"Real drives don't run at one fixed speed. Results shift with how full the drive is, how warm it is, whether something else is reading or writing to it at the same moment (Spotlight indexing, a backup, an open app), and the port, hub and cable in use. Drive makers usually quote best-case figures, so everyday results are often lower.\n\nFor a fair comparison, close apps using the drive, connect it directly with a good cable and run Run benchmark a couple of times. Storage Studio's verdict cares about whether the drive is comfortably fast enough, not about small differences between runs.","tags":["speed test","benchmark","performance"],"related":[{"id":"external-drives.do-external-ssds-get-hot","question":"Is it normal for my external SSD to get hot during big moves?","url":"/faq/external-drives/do-external-ssds-get-hot"},{"id":"external-drives.how-does-the-drive-speed-test-work","question":"How does the drive speed test in Storage Studio work?","url":"/faq/external-drives/how-does-the-drive-speed-test-work"},{"id":"external-drives.should-i-plug-the-drive-into-a-hub-or-directly","question":"Should I plug my fast drive into a hub or dock, or directly into the Mac?","url":"/faq/external-drives/should-i-plug-the-drive-into-a-hub-or-directly"}],"applies_to":"all","last_reviewed":"2026-10-01","title":"Why does the drive speed test give different results each time? — Storage Studio FAQ","description":"Speeds vary with how full and warm the drive is, other activity on it such as Spotlight, and the port and cable. Makers quote best-case numbers. Close other apps, connect directly and run the test twice for a fair reading.","crumbs":[{"name":"Home","path":"/"},{"name":"FAQ","path":"/faq/"},{"name":"External drives","path":"/faq/external-drives/"},{"name":"Why does the drive speed test give different results each time?","path":"/faq/external-drives/why-does-the-speed-test-give-different-results"}],"jsonld":{"@context":"https://schema.org","@type":"FAQPage","url":"https://storagestudio.us/faq/external-drives/why-does-the-speed-test-give-different-results","inLanguage":"en","dateModified":"2026-10-01","mainEntity":[{"@type":"Question","name":"Why does the drive speed test give different results each time?","alternateName":["Benchmark results vary","Speed test slower the second time","Inconsistent read write speeds external SSD","drive benchmark numbers change","Why is my SSD slower than advertised?","Speed test lower than the box says"],"acceptedAnswer":{"@type":"Answer","text":"Real drives don't run at one fixed speed. Results shift with how full the drive is, how warm it is, whether something else is reading or writing to it at the same moment (Spotlight indexing, a backup, an open app), and the port, hub and cable in use. Drive makers usually quote best-case figures, so everyday results are often lower.\n\nFor a fair comparison, close apps using the drive, connect it directly with a good cable and run Run benchmark a couple of times. Storage Studio's verdict cares about whether the drive is comfortably fast enough, not about small differences between runs.","url":"https://storagestudio.us/faq/external-drives/why-does-the-speed-test-give-different-results"}}]},"fragment":"
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External drives · Speed, cables and hardware

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Why does the drive speed test give different results each time?

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Short answer: Speeds vary with how full and warm the drive is, other activity on it such as Spotlight, and the port and cable. Makers quote best-case numbers. Close other apps, connect directly and run the test twice for a fair reading.

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Real drives don't run at one fixed speed. Results shift with how full the drive is, how warm it is, whether something else is reading or writing to it at the same moment (Spotlight indexing, a backup, an open app), and the port, hub and cable in use. Drive makers usually quote best-case figures, so everyday results are often lower.

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For a fair comparison, close apps using the drive, connect it directly with a good cable and run Run benchmark a couple of times. Storage Studio's verdict cares about whether the drive is comfortably fast enough, not about small differences between runs.

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