Difference between these Thunderbolt cables for an iMac?

The difference between these Thunderbolt cables are their size. One is 0.5 m and the other is 2.0 m. Buy the one you consider is enough to connect your computer to the external disk

The cables are the same, and don't expect a performance difference between them. Anyway, Thunderbolt is a high speed port, so you won't have any performance problem

The difference between the cables you are comparing is length, not thickness. The first one is one-half (.5) meter long and the second is 2 meters. Otherwise they're the same.

Regards.

Along the lines of this topic, does anyone know whether Mini DisplayPort cables are usable for Thunderbolt? Here's one, for example, that's cheaper than Apple's $29 cable:

http://www.amazon.com/exec/obidos/ASIN/B009NE77TQ/

I would be concerned about (at least) two things:

1. Can it handle the speed?

2. Does it have the right circuit?

It's possible that if it *seems* to work in a thunderbolt application, you might still run into trouble with intermittent data failure if it's not up to the task.

Thanks for any thoughts.

Mini-DisplayPort cables can only be used for connecting a display. They cannot be used for connecting a Thunderbolt storage device or other such peripheral.

Regards.

Thanks. Can you please elaborate?

I'm not sure what sort of elaboration you are expecting. If you want to connect a DisplayPort monitor, you can use a mini-DisplayPort cable. If you want to connect a Thunderbolt storage device or dock, you need to use a Thunderbolt cable. If you need more information than that, you'll need to explain what information you're looking for.

Regards.

What I was hoping you might know is the exact differences aside from the name of the cable and its intended use. Is it electrically different? If so, in what way?

Thanks.

MiniDisplayPort (MDP) cables will not transport Thunderbird protocols where as Thunderbolt cables will transport MDP protocols. The connecters are physically identical.

Thanks, that's interesting. That implies that there's logic inside the cable that processes the signal, as opposed to simple copper wire end-to-end, is that right? (well maybe not so simple, given the bandwidth required, but copper all the way, as opposed to logic in the signal path)

Yes, there is active circuitry in the TB cable that is not present in the MDP.

http://www.ifixit.com/blog/2011/06/29/what-makes-the-thunderbolt-cable-lightning -fast/

Regards.

Thanks, very interesting. According to one website, the Gennum transceiver chips used in Apple's TB cable actually have "firmware" in them. Not bad for a $50 cable that can handle those speeds over inexpensive copper conductors.