Oculink ePCIe perfect for eGPUs, competitor to TB3

[dan]

hi all,i am unaware if somebody post this before,but here is something promising regard to all egpu fans:PCI SIG to finalize OCuLink external PCI Express this fall | KitGuru

[Tech Inferno Fan]

Intel's TB3 will have a competitor soon providing x4 3.0 in the form of PCI SIG's Oculink. The Holy Grail of notebook PCs, external graphics, is coming soon via Oculink | PCWorld tells us:

<h1>The Holy Grail of notebook PCs, external graphics, is coming soon via Oculink</h1>

<h2>Oculink, designed for external PCI Express graphics on notebooks and PCs, could give laptops the graphics punch they need for gaming after hours.</h2>

<img alt="alienware amplifier cable" src="http://core0.staticworld.net/images/article/2015/04/alienware_amplifier_cable-100580642-large.jpg" />

<a href="http://www.pcworld.com/author/Mark-Hachman/">Mark Hachman</a> | <a href="https://twitter.com/markhachman" target="_blank">@markhachman</a>

Senior Editor, PCWorld

<ul> <li>Jun 23, 2015 1:14 PM</li></ul>

Every time you buy a notebook PC, you have to make a choice: low-cost integrated graphics, or expensive, discrete GPU? With the upcoming PCI Express OCuLink cable, you may not have to—you could dock your notebook into an external graphics card, instead. <em>(Editor's note: That spelling of the brand name is not a typo, but we'll be writing it as "Oculink" for the rest of this article.)</em>

And the best part? It’s almost here.

The PCI Special Interest Group (PCI-SIG) has been quietly working on the Oculink cable for at least two years. In a press briefing Tuesday, executives said that Revision 0.9 of the spec is being reviewed now, and that the final specification, version 1.0, is due in the third quarter. Historically, hardware makers have begun developing final products once the 0.9 specification was completed, implying that Oculink-capable products are just months away.

<a href="https://cms-images.idgesg.net/images/article/2015/06/oculink-usage-models-100593009-orig.png"><img alt="oculink usage models" src="http://images.techhive.com/images/article/2015/06/oculink-usage-models-100593009-large.png" style="height:369px; width:580px" /></a>

OcuLink usage models include external storage and graphics. Note the connectors built into the sides of the monitor and notebook.

“The primary usage model is as a docking cable,” said Al Yanes, president and chairman of the PCI SIG. “But it could be graphics, it could be storage, it could be networking...but yes, graphics could be one.”

<a href="https://cms-images.idgesg.net/images/article/2015/06/oculink-diagram-100593007-orig.png"><img alt="oculink diagram" src="http://images.techhive.com/images/article/2015/06/oculink-diagram-100593007-medium.png" style="height:207px; width:300px" /></a>

The OcuLink diagram. Note the pair of cables.

<h2>More bandwidth, less power</h2>

The PCI SIG is responsible for advancing the main PCI Express spec forward, but also expanding the technology outside the box, so to speak. On Tuesday, Yanes and others said that the next version of PCI Express, version 4.0, is due in the second half of 2016, with support for 64Gb/sec from a x16 connection. A version for M.2 storage (the flash storage built into tablets and some laptops) is currently in its earliest definition stages. Finally, the SIG continues to cut power, developing a “quarter swing mode” for PCIe 4.0 that will consume only 200 milliwatts. 

<a href="https://cms-images.idgesg.net/images/article/2015/06/pci-express-4.0-specs-100593006-orig.png"><img alt="pci express 4.0 specs" src="http://images.techhive.com/images/article/2015/06/pci-express-4.0-specs-100593006-medium.png" style="height:134px; width:300px" /></a>

The PCI Express progression, in terms of bandwidth.

But it’s the Oculink cable that could have the most profound impact upon the industry. 

“Oculink is pretty much done,” Yanes said. “We went through a little feedback and change from the final review.”

According to Yanes, Oculink could be used both inside and outside the PC. Inside the PC, it’s possible the cable could be used to allow extra flexibility, allowing hardware makers to place components as they like. Externally, the SIG sees Oculink as a standard cabling solution for very low-cost I/O disambiguation. 

But there’s one catch right now: the bandwidth. Right now, Oculink supports only X1, X2, and X4 widths, rather than the 16 lanes (x16) usually allocated to graphics cards. Support for x8 and x16 is coming, but in a future revision. That doesn’t mean, however, that external graphics solutions will be as underpowered as you might think—as our Gordon Mah Ung reported, <a href="http://www.pcworld.com/cms/article/Alienware,%20however,%20feels%204GB/s%20is%20plenty.%20For%20the%20record,%20Thunderbolt%202%20is%20about%202.5GB/s.%20There%E2%80%99s%20some%20testing%20to%20support%20that%20%E2%80%9Cwhatevs%E2%80%9D%20approach.%20Puget%20Systems%20found%20no%20appreciable%20difference%20between%20x16%20and%20x8%20and%20between%20Gen%202%20and%20Gen%203.%20Puget%20didn%E2%80%99t%20throttle%20it%20down%20to%20x4%20Gen%203,%20but%20it%20did%20test%20x8%20Gen%202,%20which%20is%20the%20same%20data%20rate.%20Likewise,%20Techpowerup.com%20tests%20also%20found%20no%20appreciable%20impact.">Alienware doesn’t believe that a 4X PCIe connection will be a problem</a>, and other vendors back up Alienware, too. (An X4 connection will support 32Gb/s in each direction.) The SIG says that they’ll have both copper and optical cables, as well.

[Tech Inferno Fan]

Oculink : An open source external PCIe interface, TB3 alternative, will soon be available [perhaps] suggests that BPlus is looking at creating a Oculink eGPU adapter. What remains to be seen is the uptake of Oculink by notebook manufacturers. Intel can once again stipulate conditions of usage of their chipsets and so block such technology.

<h1><a href="http://www.gaminglaptopsjunky.com/oculink-an-open-source-external-pcie-interface-tb3-alternative-will-soon-be-available-perhaps/">Oculink : An open source external PCIe interface, TB3 alternative, will soon be available [perhaps]</a></h1><h2>eGPU, external storage and more. Availability uncertain</h2>Posted by <a href="http://www.gaminglaptopsjunky.com/author/junkyadmin/">junky</a>

<a href=" " target="_blank"><img alt="Oculink PCI-SIG" src="http://pile.gaminglaptopsjunky.com/wp-content/uploads/2015/10/Oculink-PCI-SIG-300x249.jpg?7c319f" style="height:249px; width:300px" /></a>

Oculink, an open source interface / interconnection for external devices specifications is in the works for some years now by the PCI-SIG bunch. It was mentioned again by PCI-SIG in June, stating the the specifications will be finalized by the end of the year/fall.

The Oculink reminds the Thunderbolt 3 pretty much, with PCIe v.3 x4 lanes and 4GB/s (TB3 can do 5GB/s maximal, but PCIe v.3 x4 isn’t). This might be one reason Intel is hyping the Thunderbolt 3 stuff, but unlike Thunderbolt 3, the Oculink is not proprietary and you can even see this document from few days ago, with the pinout specifications (maybe not final), <a href="ftp://ftp.seagate.com/sff/SFF-9401.PDF">here</a>.

It is unclear right now how widely this will be adopted, given that the connection port is different and TB3 USB-C is already out. Also, there might be other interests involved, including easier marketing of TB3, the combination of TB3 and USB-C interface (which is very convenient and compact) and ofcourse, other marketing and commercial forces considerations. If it will be integrated into consumer systems, I wonder if it will be combined with USB-C, the same way TB3 os.

However, hwtools, the ones behind the PE4C V3.0 that enables a PCIe connection between the mPCIe in a laptop and a standard desktop size PCIe slot (thus, enabling the use of eGPU), told me that they prefer to plan for Oculink and not TB3 and that they don’t have TB3 plans. That was in response to me asking them if they plan to go with some faster connection instead of the HDMI 1.4 they currently use that is limited to PCIe v.3 x1 and thus creating a real bottleneck for many high performance GPUs, especially if you want to use the internal laptop screen and not another, external monitor. I guess EXP GDC, another manufacturer of a similar device, will have some version like this.

If such a solution will be available, even in the not-so-comfortable form of the EXP GDC / PE4C, a simple laptop with M.2 PCIe (NVMe) could be used a gaming machine with such a device, making it also way more future proof.

I wonder, though, how will the TB3, Oculink and other solutions will be integrated and why did they took so much time. It’s quite obvious that a comfortable, open source, cheap, solution like a TB3 (<a href="http://www.kitguru.net/peripherals/anton-shilov/asmedia-and-intel-cut-prices-of-usb-3-1-chips-speed-up-adoption/" onclick="__gaTracker('send', 'event', 'outbound-article', 'http://www.kitguru.net/peripherals/anton-shilov/asmedia-and-intel-cut-prices-of-usb-3-1-chips-speed-up-adoption/', 'which isn’t that expensive at all');" target="_blank">which isn’t that expensive at all</a>), is a treat for gaming laptops industry, in its current form. In general, standard open source modular solutions dismantle companies from their choking power, especially if they are backed up by PCI-SIG or similar organisations and can be produced by small 3rd party people.

Sources: <a href="http://www.kitguru.net/components/anton-shilov/pci-sig-to-finalize-oculink-external-pci-express-this-fall/" onclick="__gaTracker('send', 'event', 'outbound-article', 'http://www.kitguru.net/components/anton-shilov/pci-sig-to-finalize-oculink-external-pci-express-this-fall/', '1');" target="_blank">1</a>, <a href="http://www.pcworld.com/article/2939443/the-holy-grail-of-notebook-pcs-external-graphics-is-coming-soon-via-oculink.html" onclick="__gaTracker('send', 'event', 'outbound-article', 'http://www.pcworld.com/article/2939443/the-holy-grail-of-notebook-pcs-external-graphics-is-coming-soon-via-oculink.html', '2');" target="_blank">2</a>, <a href="http://www.edn.com/electronics-blogs/eye-on-standards/4439823/PCIe-Update--Power--IoT--storage--OCuLink--simulation--and-equalization" onclick="__gaTracker('send', 'event', 'outbound-article', 'http://www.edn.com/electronics-blogs/eye-on-standards/4439823/PCIe-Update--Power--IoT--storage--OCuLink--simulation--and-equalization', '3');" target="_blank">3</a>, <a href="ftp://ftp.seagate.com/sff/SFF-9401.PDF">4</a>