Slow USB3 speed

[joey1211]

I've installed a USB3 card in a HP Workstation. File Explorer seems to copy files over at a speed of 100-150MB/s, about average for USB3.

However, when I try cloning the system drive to an external SSD using the USB3 connection, the speed drops to USB2 speeds of 35MB/s. I've tried both Macrium Reflect and Disk Genius, same result.

The estimated time for completion is 2.5hrs but I've cloned the same size drive with about the same amount of used space at home, and it took about 20 minutes.

SSD write speeds using the cmd prompt

Actual USB2 port

New USB3 card

 

[Cyber-Mav]

Which external SSD are you using?

 

[iamgigglz]

File Explorer seems to copy files over at a speed of 100-150MB/s

For how long? You might be filling your external SSD's cache with the multi-GB clone. Try using file explorer to copy the biggest file you can to the drive. The speed might start off quick and then suddenly drop as the cache fills up.
Could also be the controller on the SSD or even on the USB3 card overheating and throttling.

I've cloned the same size drive with about the same amount of used space at home, and it took about 20 minutes.

Same external drive?