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What is Oculink? It sounds like the tech that Dr. Octopus uses

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to control his robot arms, legs, but it's actually an open standard PCI Express connector

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with a compact form factor created to compete with Thunderbolt and USB.

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Despite being around for nearly a decade, Oculink has remained a relatively obscure standard,

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which is a shame because it's actually pretty awesome.

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Oculink stands for optical copper link and was initially envisioned as a combination

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of copper and optical fiber. However, the need to convert electrical signals

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into light signals and back again means that fiber optics are relatively inefficient

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over short distances. So the whole optical element was eventually scrapped,

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though the name remains. CU stands for copper's chemical symbol,

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which is itself based on copper's Latin name. Otherwise, it would be spelled acolink,

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and I think we can all agree that's just terrible. Aco, acolink?

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Oculink was developed by PCI SIG,

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the body charged with creating standards for the PCI interface.

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Oculink 2.0, the most recent version, launched in 2017 with a new connector,

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similar to the standard DisplayPort connector. It boasts support for up to four PCIe 4.0 lanes

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and up to eight gigabits per second per lane for a total of 64 gigabits per second of bandwidth,

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though notably an eight lane version also exists.

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That places the four lane version above both Thunderbolt 3 and 4

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in terms of transmission speed and on par with Intel's upcoming Thunderbolt 5,

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which is supposed to launch sometime in 2024 with 80 gigabits per second of bi-directional bandwidth,

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but only 64 gigabits per second of PCIe bandwidth.

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Now beyond bandwidth, a primary advantage of Oculink is that it's far more cost effective.

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That was particularly the case prior to 2018

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when Thunderbolt became a royalty-free standard, but it's still true, albeit to a lesser degree,

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simply because it uses cheaper components and doesn't require quite the same amount

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of precision to manufacture. It's that combination of high performance

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and a lower price point, which has garnered Oculink a devoted following,

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especially on the server side. Now that doesn't mean there's no consumer side applications.

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Oculink reduces the performance gap between internal and external GPUs to a very low margin

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because it's significantly faster than Thunderbolt 3 or 4. What Oculink doesn't do, that Thunderbolt does,

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is provide solid support for hot plugging. With Oculink, you're typically going to want

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to shut down the system before swapping components, or it might crash.

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Oculink only uses PCIe signals, making it great for connecting a graphics card,

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network card, or storage controller, but Thunderbolt is basically a two-in-one DisplayPort

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slash PCIe connector, which can provide video

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in addition to power and data transfer. Oculink only transfers data,

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so an Oculink setup is always going to need at least two cables if you want to connect

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and power a device at the same time. Not to mention that Thunderbolt ports are compatible

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with USB-C cables. These factors, plus having daddy Intel as a backer,

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mean that Thunderbolt has much broader adoption in the consumer electronic space.

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And that ubiquity gives Thunderbolt a definite advantage

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in terms of convenience, especially for less tech-savvy users.

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Now, you could, hypothetically, create a version of Oculink with some or all

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of the bells and whistles that Thunderbolt offers, but that might be missing out

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on what makes Oculink truly great.

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Thunderbolt is designed to be a generalist connector, a jack of all jacks, if you will.

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It's made to do several different things quite well, wrapped up in a convenient user-friendly package,

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but generalization comes at the expense of specialization,

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and lower data transfer speeds and throttling are a result of that compromise.

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A similarly flexible and multi-purpose Oculink connector

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would also probably be far more expensive, because when you're combining a bunch of complex components

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exchanging a bunch of different signals in a very, very small space,

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that demands both creative engineering and extremely precise manufacturing.

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Otherwise, there's gonna be interference between these different signals, and it won't be reliable.

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Thunderbolt 5 is supposed to give us the best of both worlds,

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the convenience and versatility of earlier versions of Thunderbolt,

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but with far faster data transfer speeds.

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It'll be a while before we can see real-world benchmarks, but I mean, that sounds awesome.

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It bears remembering, however, that so long as these connectors remain a bottleneck,

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and performance loss is non-trivial, there will always be space for an improved version

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of the Oculink or another specialized connector to come along and do it better.

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Here's open, cheers. And cheers to you for watching the whole video.

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