External drives through my USB-C dock are 5x slower than directly into the laptop. A 1-hour backup now takes half a day.
A USB-C dock that promises USB-3 or Thunderbolt usually delivers a bit less. For large sequential writes, direct attach or a Thunderbolt NVMe enclosure is far faster.
Try this first
- 1Read the dock spec. Many 'USB-C docks' are DisplayLink (over USB 3.0) or just a USB-3 hub. 1 TB over USB-3 (5 Gbit/s) is theoretically 30 minutes, more in practice with overhead.
- 2Test direct: plug the same drive into the laptop with a short USB-C cable next to the dock. Diff over 2x means the dock or cable is the bottleneck.
- 3For Thunderbolt docks: not every USB-C port is Thunderbolt. Look for the lightning icon. A dock on a non-TB port works at USB-3 speed and gives no warning.
- 4Swap cable: 'Charge only' or 'USB 2.0' USB-C cables drop you to 480 Mbit/s. A marked 'USB 3.2 Gen 2' or 'Thunderbolt 4' cable is worth a test.
- 5Measure with CrystalDiskMark or 'dd if=/dev/zero' (Mac/Linux). Expect SATA SSD over USB-3 around 400 MB/s, NVMe over TB4 around 2.5 GB/s.
- 6For backups consider a Thunderbolt NVMe enclosure directly on the laptop, or schedule overnight jobs against the dock drive when speed matters less.
When to bring us in
If speed stays poor, the dock itself may overheat and throttle. Check whether the dock runs hot and look for vendor firmware updates.
See also
- My laptop is suddenly slowThree main suspects: a runaway background process, near-full disk, or a Windows update in progress.
- One specific application is slow for everyoneIf an app is slow for one person: local. For everyone at once: server side or vendor side.
- Opening files from the file server takes minutesOften the server itself is fine and the issue is network routing or stalling DNS resolution.
None of the above fits?
Describe your situation below. We pass your input plus the steps you already saw to our AI and return tailored next-step advice. If it's too risky to DIY, we'll say so.
Or skip the DIY entirely
Our Managed IT clients do not look these things up. One point of contact, a fixed monthly price, resolved within working hours.