Can a 2017 iMac connect to 2 Thunderbolt 4 docks, each with more TB4 plugs?

[iHavequestions]

Just wondering if this will work. Each thunderbolt doc has 3 more thunderbolt downstream plugs for a total of 6 thunderbolt plugs. Most of them will connect to SSDs.

 

[iHavequestions]

I guess the only way to know is to try it. No one here seems to have a response!

 

[gilby101]

I guess the only way to know is to try it. No one here seems to have a response!

Yep.

I take you are considering things like this https://eshop.macsales.com/shop/owc-thunderbolt-dock

The only thing I can offer is to remember that the iMac only has one Thunderbolt controller (even though two connectors), so you are limited to a total of 40 gb/s. I guess (don't know) that would be fine for attached storage (which will just slow down), might be more of an issue if you were also connecting maximum number of screens (2 x 4K).

 

[iHavequestions]

Yep.

I take you are considering things like this https://eshop.macsales.com/shop/owc-thunderbolt-dock

The only thing I can offer is to remember that the iMac only has one Thunderbolt controller (even though two connectors), so you are limited to a total of 40 gb/s. I guess (don't know) that would be fine for attached storage (which will just slow down), might be more of an issue if you were also connecting maximum number of screens (2 x 4K).

Thanks for that insight. It would only slow down in the case of concurrent file transfers right? Or If there's an external monitor running at the same time as a file transfer as well?

 

[gilby101]

It would only slow down in the case of concurrent file transfers right? Or If there's an external monitor running at the same time as a file transfer as well?

You need an answer from someone with direct experience particularly if you intend multiple Thunderbolt SSDs and external monitor(s). My comments were based on general principals re sharing 40 Gb/s.

 

[MRxROBOT]

Just wondering if this will work. Each thunderbolt doc has 3 more thunderbolt downstream plugs for a total of 6 thunderbolt plugs. Most of them will connect to SSDs.

Yes, it will work just fine. Total bandwidth remains the same however.

 

[padams35]

Yep.

I take you are considering things like this https://eshop.macsales.com/shop/owc-thunderbolt-dock

The only thing I can offer is to remember that the iMac only has one Thunderbolt controller (even though two connectors), so you are limited to a total of 40 gb/s. I guess (don't know) that would be fine for attached storage (which will just slow down), might be more of an issue if you were also connecting maximum number of screens (2 x 4K).

No, the 40 Gbps limit is for each connector including overhead.

The bus/controller limit is DisplayPort 1.2 x2 + PCIe3.0 x4, which adds up to a theoretical 66.56 Gbps maximum data rate for combined video+data shared between the ports.

Thanks for that insight. It would only slow down in the case of concurrent file transfers right? Or If there's an external monitor running at the same time as a file transfer as well?

Correct, but a single external monitor shouldn't slow anything down unless you are trying to run a 5K or 6K display.

 

[iHavequestions]

No, the 40 Gbps limit is for each connector including overhead.

The bus/controller limit is DisplayPort 1.2 x2 + PCIe3.0 x4, which adds up to a theoretical 66.56 Gbps maximum data rate for combined video+data shared between the ports.


Correct, but a single external monitor shouldn't slow anything down unless you are trying to run a 5K or 6K display.

Thanks so much for that insight!