Retina MBP's 2 Thunderbolt Ports

[///KM]

Anyone have any information on the 2 Thunderbolt ports on the RMBP, specifically: is it 2 x 10Gbps ports on 2 PCIe connections, or do the 2 ports share a 10Gbps PCIe connection, effectively halving the bandwidth if the two ports are in use?

Apple's specs are unclear: "Two Thunderbolt ports (up to 10 Gbps)"

 

[Moriarty]

I don't know how the PCI-Express bus design has changed with the new processors. But on the 2011 iMac, there is only one 20 Gbps PCI-E bus, which the two Thunderbolt ports share. I suspect the new Pro is the same.

http://www.anandtech.com/show/4340/27inch-apple-imac-review-2011/3

It's a poorly publicised limitation that could have consequences for a select few people... but Apple should say more about it nevertheless so people running lots of high end I/O and displays don't run out of bandwidth (that could cause much more nasty problems than say just having lots of USB devices on a hub hogging bandwidth, I suspect).

 

[Stetrain]

This most likely uses the brand new Cactus Ridge controller for Thunderbolt:

The 3510 has four TBT lanes, to DP sink, two DP (DisplayPort) source, and four PCIe lanes with the TDP of 3.4 W or 2.8 W.

http://www.slashgear.com/intels-sec...-ridge-thunderbolt-controller-ships-12222574/

So it looks like four 10GB lanes, two per port. Basically double the usable bandwidth of the previous gen MBP.

Edit: It may also use the previous gen Light Ridge controller which has similar specs:

Light Ridge is the bigger chip that features four Thunderbolt channels (4 x 10Gbps bidirectional = 80Gbps aggregate bandwidth) and two DisplayPort outputs

http://www.anandtech.com/show/4772/meet-the-2012-thunderbolt-controllers-cactus-ridge

 

[///KM]

This most likely uses the brand new Cactus Ridge controller for Thunderbolt:



http://www.slashgear.com/intels-sec...-ridge-thunderbolt-controller-ships-12222574/

So it looks like four 10GB lanes, two per port. Basically double the bandwidth of the previous gen MBP.

Edit: It may also use the previous gen Light Ridge controller which has similar specs:



http://www.anandtech.com/show/4772/meet-the-2012-thunderbolt-controllers-cactus-ridge

Thanks mate I guess we'll find out which controller is in use once iFixit does their teardown and/or Anandtech publishes their review.

 

[Stetrain]

Thanks mate I guess we'll find out which controller is in use once iFixit does their teardown and/or Anandtech publishes their review.

As far as I can tell there isn't any real difference in features and performance between them, just physical size and cost.

 

[///KM]

According to the iFixit teardown, looks to be the DSL3510L Cactus Ridge controller I hope this means both ports get the full 10Gbps, double the bandwidth!

 

[Erasmus]

According to the iFixit teardown, looks to be the DSL3510L Cactus Ridge controller I hope this means both ports get the full 10Gbps, double the bandwidth!

I believe both ports should be able to run at 20 Gbit/s, as they are both dual channel 10 Gbit/s.

I still don't really understand how Thunderbolt works, but I am assuming that each port contains one 10Gbit/s PCIe lane, and another lane that can either operate as a second 10Gbit/s PCI lane, or DisplayPort.

Wondering how long it takes companies to start developing external PCIe housings that can take all four thunderbolt lanes, and connect them to two high end desktop GPUs in Crossfire/SLI...