Dear friends
I just bought an awesome owc Express 1m2 TB case to fit a Samsung 990 pro 4 tb and whereas I get Full Speed at my MacBook Pro M1 Pro (2021), namely 3100 MB/s, iMac it recognizes as usb3.1 and Both Thunderbolt Ports 40 gbps appear empty (System Report). As a consequence I get only 980mb/s. I tried everything with restarting, ram reset, Safe Mode… Any thoughts? Thanks
Michael
iMac 27″
I had the same issue. The cause is the TB enclosure which is designed for TB4 port Macs. I assume the slower speed is on the write side and higher on the read? What you need is a different enclosure. I switched to an Acasis enclosure and now my speeds are at about 2700-2800 on both W and R.. Even though many enclosures state compatible with TB3 all that means it will work but not necessarily at the fastest speeds. The latest TB enclosures use a new chip that provides very fast speeds (on TB4) but do not work with TB3 ports. I use this enclosure with my 2019 27" iMac i9 to boot from:
https://www.amazon.com/dp/B0C8CZB5S7?ref_=ppx_hzsearch_conn_dt_b_fed_asin_title_1&th=1
You can also buy the same version without the fan
I had the same issue. The cause is the TB enclosure which is designed for TB4 port Macs. I assume the slower speed is on the write side and higher on the read? What you need is a different enclosure. I switched to an Acasis enclosure and now my speeds are at about 2700-2800 on both W and R.. Even though many enclosures state compatible with TB3 all that means it will work but not necessarily at the fastest speeds. The latest TB enclosures use a new chip that provides very fast speeds (on TB4) but do not work with TB3 ports. I use this enclosure with my 2019 27" iMac i9 to boot from:
https://www.amazon.com/dp/B0C8CZB5S7?ref_=ppx_hzsearch_conn_dt_b_fed_asin_title_1&th=1
You can also buy the same version without the fan
Sounds like a cabling issue. Are you using the same Thunderbolt cable to test on both your laptop and the iMac?
tbirdvet's comment made me remember a statement that I saw recently on OWC's website when shopping for external storage. Have a look on the page https://www.owc.com/solutions/express-1m2 and there is a nice table entitled "As Fast as Your Computer or Device" that states 990MB/s on Mac with TB3. It then goes on to a section "Don’t Get Fooled" that states "While specific OWC solutions are certified for full speed on Thunderbolt, we (and everyone else) are limited to half that speed with DIY enclosures."
I know this is not a solution for you but it's information to consider when reading other vendor's specifications.
I also find this value for money, if anyone has tested the compatibility for iMac 2019
Yes, I used the original TB4 cable by OWC that was included with the ssd external case
I also have the latest MacOs version installed in both machines
Thank you again
thank you for your Insights. I assume I have to Return the enclosure and get another one
do you have Experimente if this Model is going to work?
best
Michael
This is the same one I have without the fan so should work fine.
Thunderbolt 3 issue in iMac i9 27 2019
