Hey everyone! I'm trying to figure out an issue with my setup. I have a Samsung 990 Pro SSD connected to an ASRock X570 Pro4 motherboard through the ASRock Thunderbolt 3 AIC card, and I'm using an external Acasis enclosure with another Samsung 990 Pro installed. When I transfer data from the external SSD to the internal one, the speed is great at nearly 3GB/s. But when I do the opposite—writing from the internal SSD to the external one—the speed plummets to only about 300MB/s. I'm using the same Thunderbolt cable for both directions, so I'm confused as to why the speed difference is so drastic. What might be causing this issue?
3 Answers
What external drive are you writing to? Understanding the full setup might help pinpoint the issue.
Do the write speeds start off high and then dip down? If that's happening, it might be a thermal issue. But if it's consistently 300MB/s, that points to something else.
It's a steady 300MB/s from the start to the finish; no initial speed bump. The enclosure has a fan and I've added a thermal pad to the SSD, so I don’t think it’s heat related.
First off, make sure that all your devices—the ports, the enclosure, and the cable—are actually Thunderbolt 3 certified, not just USB-C compatible. Sometimes, devices that share the USB-C connector can be misleading. Also, double-check if you’re plugged into the correct Thunderbolt port on your motherboard.
Thanks for the tip! I've checked everything and I'm in the right ports, but I'm still seeing those slow speeds from internal to external.
Both the internal and external drives are Samsung 990 Pro 4TB, so they're identical.