Has anybody come across this problem? Can anyone make any suggestions? I hope I don't have to return the Blackmagic Multidock and find something else. I also tried to reset PRAM and SMC, just for a what if. When he powers up his computer, the SSD drives are detected immediately as normal. Anyway, he does not have any such problem with his system. Otherwise, he has the same identical SSD drives as I do (OWC Mercury Extreme Pro 6G). So he had to buy an Apple adaptor cable (Thunderbolt 2 to USB-C). And his Blackmagic Multidock is the older version, with the Thunderbolt 2 connectors. Except that his iMac Pro is running the previous OS X High Sierra. I should also mention that a friend of mine has an almost identical setup. I plugged it into the iMac Pro that was there on display (which was running OS X 10.4.6 Mojave), and the same thing happened. Today, I took my Multidock down to the local Apple store. The SSD drives only are detected if I unplug and re-plug the USB-C cable from the back of the iMac Pro, while the iMac Pro is up and running. I have repeated this process countless times and it's the same problem each time. However, when I tried to unplug the USB-C cable (from the back of the iMac Pro) and then plugged it back in, suddenly, the SSD drives appear. They don't show up on the desktop, nor do they show up in Disc Utility. With everything connected and plugged in, when I power up my Imac Pro, it does not detect the SSD drives. And my USB-C cable is plugged into the "A" connector. On the back of the Multidock, I have the switch in the "4" position (to use all 4 slots on the same A bus). In the Multidock, I have 2 SSD drives, OWC Mercury Extreme Pro 6G, inserted in the first 2 slots of the Multidock. I connected the iMac Pro with the Multidock via USB-C cable (the cable was bought at OWC Macsales, for what it's worth). I also have a new iMac Pro (2017 model), running OS X 10.14.5 Mojave. But since the MultiDock 10G uses SATA 3 (6 Gbps) based connections to the actual drives themselves, the maximum throughput possible to a single drive is even lower, usually around 500 MB/s maximum after accounting for SATA interface overhead (and could be less depending on the drive).I just purchased the brand new Blackmagic Multidock 10 G. USB 3.1 Gen 2 bus speeds are 10 Gbps (1250 MB/s) at the interface level, but due to overhead and other issues, real world maximum performance you can expect at the port level is around 900 MB/s or so. Sometimes this is due to connection related issues and disconnecting and reconnecting the cable improves things.Įven with USB 3.1 Gen 2 speeds, things are never going to be as fast through the MultiDock 10G as with the internal SSD. I've also seen situations where USB 3 capable ports don't always negotiate USB 3 speeds (even when using a USB 3 compatible cable). For example, a lot of USB-C cables designed for charging purposes only support USB 2.0 data speeds as they lack the additional data wires internally to support USB 3 data transfers. Usually the causes of this are some kind of cable or port issue. Although USB 2.0 has a maximum interface bandwidth of 480 Mbps (60 MB/s), due to interface overhead (and a few other factors), have real world transfer speeds in the range of 35 to 40 MB/s, which seems to be inline with what you are seeing. It sounds like the MultiDock 10G is only connected to the computer using USB 2.0 speeds (480 Mbps) rather than USB 3.1 Gen 2 speeds (10 Gbps).
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