# Questioning drives actual speed Sandisk Extreme Pro 4TB

**URL:** <https://forums.sandisk.com/t/questioning-drives-actual-speed-sandisk-extreme-pro-4tb/417946>\
**Category:** Portable | Extreme | Extreme Pro SSD\
**Tags:** extreme-pro-portable\
**Created:** [December 4, 2025, 7:23am UTC](https://forums.sandisk.com/t/questioning-drives-actual-speed-sandisk-extreme-pro-4tb/417946 "2025-12-04T07:23:48Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Sp2222](https://sea2.discourse-cdn.com/sandisk/user_avatar/forums.sandisk.com/sp2222/32/69479_2.png) [@Sp2222](https://forums.sandisk.com/u/Sp2222)\
**Post date:** [December 4, 2025, 7:23am UTC](https://forums.sandisk.com/t/questioning-drives-actual-speed-sandisk-extreme-pro-4tb/417946/1 "2025-12-04T07:23:48Z")

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When moving large files the max speeds I get on a thunderbolt 4 usb c port is ~900 mbps. Crystal disk mark shows this result, which appears normal, but i want to make sure that the results ive seen are normal.

 ![1000002888](https://global.discourse-cdn.com/sandisk/original/3X/b/0/b030a44f8237394d19f3a2267d738852e59b4915.png)

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**Author:** ![suruguri.chaithanya1](https://avatars.discourse-cdn.com/v4/letter/s/54ee81/32.png) [@suruguri.chaithanya1](https://forums.sandisk.com/u/suruguri.chaithanya1)\
**Post date:** [December 6, 2025, 12:20pm UTC](https://forums.sandisk.com/t/questioning-drives-actual-speed-sandisk-extreme-pro-4tb/417946/2 "2025-12-06T12:20:41Z")

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Hi @Sp2222

Have you checked our knowledge base articles?  
([Get Support for Your SSDs and Flash Products | Sandisk](https://shop.sandisk.com/support))

Have you opened a Support Case?  
If not, contact SanDisk Technical Support for assistance.  
([Contact Support | Sandisk](https://shop.sandisk.com/support/contact-us))