LAB501

eGPU – Connecting an external video card to a notebook (DIY implementation)

First thing, like already mentioned on the previous page, we need a notebook with Thunderbolt support. We are going to use an Asus ROG notebook from G750 series, a 17 inch gaming machine, featuring an Intel Haswell i7 4700HQ CPU and a discrete graphics card like Nvidia 765m.

asus_g750jw

Asus G750JW model features a Cactus Ridge DSL3310 Thunderbolt chipset, capable to power a single Thunderbolt connection port. For the PCI Express Expansion board, I’ve opted (at that time) for a Sonnet Echo Express SE.

sonnet-cardboard

It comes in an aluminium enclosure and is bundled with a 12V adapter to provide up to 60W of power for the Thunderbolt chip inside and for the PCI Express card that should be installed.

sonnet-all

The Sonnet Echo Express SE solution is based on two boards, a daugherboard featuring a PCI Express slot with a 8x width and the main board with the Thunderbolt chipset soldered on it.

sonnet-first

sonnet-outside

sonnet-side_by_side1

While the PCI Express slot/socket should allow one half-length (up to 6.6″ long), single-width, full-height x8 PCIe 2.0 card, the electrical connection is limited to a x4 PCIe 2.0 (because the actual electrical bandwidth of Thunderbolt is x4). The slot is not allowing us to install a full length x16 board like a modern video card, because the end of the slot is closed. Such an issue can be avoided by using a PCI Express riser, or using some tool like a sharp knife to carve in the plastic to make the card slide in properly.

Hey! Told you this is a DIY project, right?

7 comments la: eGPU – Connecting an external video card to a notebook (DIY implementation)

    1. So you left out the most important information, the penalty of thunderbolt/usb3 and the memory buffering. The most important reasons you see few/no such implementations in the wild.

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    2. Compared to desktop, yes. Compared to the dGPU in the laptop…you can see the graphs…

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    3. Awesome stuff Monstru! Like it 🙂 Now I want to attach this to my MacBook Pro Retina and do some 3k gaming on it 😀

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    4. Glad you like it, I hope it helps a lot of users 😀

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    5. Great work!!! Would it be possible to run the pcie with a powered riser? The Sonnet Board needs still be powered, right? Possible to power it through PSU? Thanks

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    6. Joseph wrote on:

      I don’t know whether or not I should be posting this here, but I’m having a problem with an egpu unit, when ever I attatch it to my laptop and boot up (either with or without the drivers) my laptop screen on boot up goes to a GPU fail screen (multicoloured and pixelated). I’ve yet to find anyone else with the same problem and from my testing I’ve yet to find a solution :'( .

      If anybody could help me solve this problem I would be over the moon 🙂

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    7. What a great explanation. Thanks! From the moment I saw the bandwidth of thunderbolt I knew this would be possible and I am sure there is a commercial market for it. Meanwhile, hopefully more and more enclosures come out with boards which can help make this easier still.

      …and sure, it won’t beat a desktop with the same GPU, but it gives you the chance to have an ultra portable with desktop class graphics which is also upgradable! Brilliant!

      Reply

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