View Full Version : Does Thunderbolt 2 slow down with Thunderbolt 1 devices hooked up?


Shaun Roemich
January 26th, 2015, 05:04 PM
Hey folks... I really didn't know where to put this so I thought I'd add it to the newest Apple specific subforum.

So the new iMacs come with two Thunderbolt 2 ports.

In the old days, Firewire 400 devices attached to Firewire 800 ports slowed down ALL Firewire devices on that controller - in most cases all Firewire busses on that computer unless a secondary Firewire card was added to a PCI slot in a tower.

Does Thunderbolt do anything like this?

I'm wondering specifically if I can buy a new iMac and attach one (or more) Apple Thunderbolt Display(s) (legacy TB1) to one Thnderbolt 2 port and maintain Thunderbolt 2 performance on all the daisy chained peripherals on the non-Thunderbolt Display-attached port?

David Sholle
January 26th, 2015, 08:24 PM
I read something about this recently, but can't find the article now. What I remember reading is that if you are going to daisy chain a TB and a TB 2 device on the same TB port on the computer, you want to daisy chain in this manner:

Computer with TB 2 port connected to TB 2 device connected to TB device

If, instead, you put the TB device first in the chain, it can only communicate with the following TB 2 device at TB speeds. That makes sense, as the TB device would have TB chips in it, and not TB 2 chips.

Unfortunately my MBPr is somewhat older, so it doesn't have TB 2 ports, so I can't check this out. I plan to upgrade when they refresh the MBPr.

Some further information that might be useful if you are maxing out TB 2 speeds is found in this article on the Mac Pro (probably doesn't apply in your case):

MPG - Understanding Thunderbolt and USB3 Performance with the 2013 Mac Pro - 2013 Mac Pro: Thunderbolt Performance Tips (http://macperformanceguide.com/MacPro2013-Thunderbolt-performance-tips.html)

Shaun Roemich
January 26th, 2015, 09:07 PM
Thanks David, that's what I THOUGHT but wasn't sure.