He Guys, 

 

I was hesitant about asking this question but I could not find a clear enough answer on the forum. Maybe there is somewhere. In that case I apologize, please point me in the right direction/topic. 

 

So I was wondering why a harddisk plugged in directly to a usb 3.1 port and writing a large amount of data to a nvme cache drive is only getting around 125 mb/s write speeds. Some of the answers/sugestions I read was that it was due to parity. But writing directly to the cache drive this should not matter. I am not expecting to get 2.000 mb/s write speeds! But I just don't understand the 125 mb/s limit. Is it something to do with the NVMe? 

 

external hard disk

 

WDBWLG0020HBK-EESN

2TB platter, USB3.0 

 

cache drive

 

PNY XLR8 CS3030 500GB

500GB, 3d v-nand (TLC), NVMe

 

thanks in advanced, gr Piet

tower-diagnostics-20210121-0924.zip

1 hour ago, poeterdebier said:

a harddisk plugged in directly to a usb 3.1 port and writing a large amount of data to a nvme cache drive is only getting around 125 mb/s

2TB 5400rpm hard drive can't do much more than that, you can test with the diskspeed docker.

Damn, feel like a idiot. Never occurred to me to search for 5400 or 7200 rpm max read/write. Would never have guessed that the bottleneck was there. Thanks for clearing that up Jorge.