PCIe and Thunderbolt 2 make things simpler

What a convergence we are seeing in the PC world. The world used to be filled with lots of different buses (serial, parallel cables, IDE, PCI) but as performance has increased the world has converged around serial buses (because it when things go really fast it is hard to make the signals across multiple lines work right, you’d rather have lots of separate serial lines than try to coordinate signals across 64 lines) and in massive integration so caches and things now are on chip.
The good news is that this makes connecting things easier than ever as the new Mac Pro and the MacBook Air announcements show. Specifically:

  1. The move to PCIe SSD. The world has finally recognizes that the old hard drives don’t need a special connector (IDE, SATA, SAS), but instead you put all the flash into a PCIe card (typically 2 lanes or 2 links or 2 channels) and you get incredible performance. With SATA 6GB, you can get about 500MBps (we hooked up a pair with RAID-0 and got 1GBps) or just use PCIe and get 1GBps from the get go. The world now has native PCIe disk controllers which was the big step. It also means that for conventional PCs, we can get rid of all that cabling that goes to SATA devices (like in our aquarium PC and replace it with a single PCI SSD), that is great
  2. Thunderbolt 2. Intel’s technology update which is essentially take a PCIe stream out of the box to other devices. The original Thunderbolt had four PCIe 2.0 lanes or four 10Gbps channels (two upstream and two downstream) so for any single device, the most performance you could get is 10Gbps which for storage is about 800-900MBps, but 4K resolution requires 15Gbps. Thunderbolt 2 allows channel bonding so you can get two bidirectional 20Gbps channels so it works with 4K displays using Displayport 1.2 and also should help on disk throughput to a theoretic 1.5GBps. This isn’t using PCIe 3.0, but that’s probably around the corner.

The net is the world is moving to PCIe as a wired standard and to Gigabit wifi 802.11ac for wireless. It is a wonderful world! Or course there will also be USB 3.0 for the random peripherals as well which using a similar technique as PCIe by the way providing 5Gbps raw in the new Superspeed mode which will give 400MBps in practice given transport overhead. So the world is indeed fast, fast, fast these days.

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