DK’s Cool eGPU Experience – Part 2: Thunderbolt 3

DK/ December 15, 2019/ eGPU Series

  • Sonnet eGFX Thunderbolt 3 Breakaway Box sitting on a shelf with the outer cover removed revealing the Gigabyte Radeon RX 570 4GB within
    The Gigabyte Radeon RX 570 4GB inside the enclosure with its cool lights
  • HP ZBook Studio G3 sitting on a shelf
    HP ZBook Studio G3 (2016)
  • Sonnet eGFX Thunderbolt 3 Breakaway Box sitting on a shelf with monitor cables plugged into it
    Sonnet eGFX Thunderbolt 3 Breakaway Box
  • HP ZBook Studio G3 with an eGPU and 7 external monitors plus the laptop screen
    This setup supports 7 external monitors plus the laptop screen for a total of 8 monitors
  • The right side of an HP ZBook Studio G3 showing the power, headphone, USB, HDMI, and Thunderbolt 3 ports with cables plugged into them.
    Those are the Thunderbolt 3 ports. They look like USB-C ports. They are also those.
  • Sonnet eGFX Thunderbolt 3 Breakaway Box sitting on a shelf with the outer cover removed revealing the Gigabyte Radeon RX 570 4GB within
    The Gigabyte Radeon RX 570 4GB inside the enclosure
  • Sonnet eGFX Thunderbolt 3 Breakaway Box sitting on a shelf with the outer cover removed revealing the Gigabyte Radeon RX 570 4GB within and a closeup of the PCIe interface board
    A closer look at the PCIe interface board
  • Sonnet eGFX Thunderbolt 3 Breakaway Box sitting on a shelf with the outer cover removed and the cool glow of the blue LEDs on the front
    The cool blue glow of the front panel LEDs
  • Hitman 2 (2018) by IO Interactive, Agent 47 standing on a dock at the beach
    Agent 47 at the beach in medium quality at 2560x1440 resolution.

What is so special about using Thunderbolt 3 for an eGPU?

Thunderbolt 3 (TB3) uses a USB-C connector and supports PCIe x4. The EXP GDC Beast from Part 1 operated at x2 over mini PCIe on the Lenovo ThinkPad T420.

The right side of an HP ZBook Studio G3 showing the power, headphone, USB, HDMI, and Thunderbolt 3 ports with cables plugged into them.
Those are the Thunderbolt 3 ports. They look like USB-C ports. They are also those.

Thunderbolt 3 enables a bunch of other things too. The big deal is that it supports video in addition to regular USB devices.

Manufacturers of TB3 compatible hardware are required to purchase a license from Intel, which has pushed up the price of TB3 certified hardware, especially when compared to the EXP GDC Beast.

What is an eGPU again?

As described in Part 1, the term "eGPU" refers to an external graphics processing unit. It is a video card that is externally attached to a computer, and not integrated or attached inside of a case. An "eGPU dock" is the adapter used to connect the video card to the computer. The term "enclosure" might be used in place of "dock" for adapters that feature a housing for the video card.

eGPUs and systems built to accommodate multiple video cards can be used for cryptocurrency mining.

Thunderbolt 3 eGPU Starter Pack:

HP ZBook Studio G3 (2016)

HP ZBook Studio G3 sitting on a shelf

Alias: HP ZBook, computer, machine, laptop
Specs: Quad-core i7-6820HQ / M.2 NVMe 512GB SSD + M.2 NVMe 1TB SSD / 32 GB RAM / nVidia Quadro M1000M 4GB / Intel HD 530 / 4K
Acquired via: eBay

Gigabyte AMD Radeon RX 570 4GB

Sonnet eGFX Thunderbolt 3 Breakaway Box sitting on a shelf with the outer cover removed revealing the Gigabyte Radeon RX 570 4GB within

Alias: eGPU, video card
Acquired via: Newegg clearance

Sonnet eGFX Thunderbolt 3 Breakaway Box

Sonnet eGFX Thunderbolt 3 Breakaway Box sitting on a shelf with monitor cables plugged into it

Alias: eGPU enclosure
Compatible slots: Thunderbolt 3
Acquired via: eBay
Notes: Integrated power supply, has one TB3 port and one power connector and a power switch

How does it work?

The eGPU enclosure contains the video card. It plugs into the Thunderbolt 3 port on the computer. Unlike the EXP GDC Beast from Part 1, the computer will not have to be partially disassembled in order to use the eGPU. All I have to do is unplug the cable, and the computer goes right back to being portable.

Sonnet eGFX Thunderbolt 3 Breakaway Box sitting on a shelf with the outer cover removed revealing the Gigabyte Radeon RX 570 4GB within

One major difference between this solution and the EXP GDC Beast from Part 1 is that the TB3 eGPU is not detected by the system as a video device at boot. This means that Windows resumes on the laptop screen after powering on, but only until the eGPU is detected and the monitor profile is loaded by DisplayFusion/Windows. In constrast, the eGPU dock in the Lenovo T420 was connected to a native PCIe port, which allowed the system to recognize the hardware as a video device on boot. This does not sound like a big deal until you experience window position loss, where all of the windows you had open across multiple monitors are now stacked on the primary monitor. More about that later.

As for performance bottlenecks, the hardware in this configuration is much newer and faster. The average bottleneck value is 0.61% according to this bottleneck calculator. However, the calculator assumed that the video card would be plugged into a PCI-E x16 slot, not a Thunderbolt 3 PCI-E x4 slot. This means that the real bottleneck value is actually higher.

But as was the case in Part 1, the bottleneck does not really matter. It still performs way better than both the integrated video adapter and the nVidia Quadro M1000M, both of which support only three external monitors. With the eGPU, the system now supports 8 total monitors (7 external plus the laptop screen).

HP ZBook Studio G3 with an eGPU and 7 external monitors plus the laptop screen
This setup supports 7 external monitors plus the laptop screen for a total of 8 monitors.

I typically only use the 5 monitors that are plugged into the eGPU. This system has an nVidia card, but the eGPU is an AMD card. To avoid issues, I disabled the nVidia card in the BIOS, and the laptop screen in Windows when the eGPU is plugged in and working.

It also supports VR (virtual reality)

Oculus Quest 2 and controllers sitting on a shelf

COMING SOON: The VR series will kick off with using this setup to power an Oculus Quest 2 over both Oculus Link and the Virtual Desktop Streamer.

Spoiler alert: The Virtual Desktop streaming solution for the Quest 2 works way better than Oculus Link at this point, but neither solution is perfect. This setup also runs into performance issues with No Man's Sky VR and H3VR, among others. However, it runs The Talos Principle VR and Google Earth VR extremely smoothly, even when using the nVidia Quadro M1000M and not the eGPU.

Plus it's totally cool, dude. This one appears to carry a low to moderate risk of assimilation due to the metal case.

Sonnet eGFX Thunderbolt 3 Breakaway Box sitting on a shelf with the outer cover removed revealing the Gigabyte Radeon RX 570 4GB within

What could possibly go wrong?

This solution is much more refined than the solution from Part 1. Only two cables are required, and one of them is a standard computer power cable. However, things can still go wrong.

There might be a power loss.

The laptop has a battery. The eGPU does not. When the power goes out, the eGPU loses power and disconnects from the laptop.

One theoretical solution is to plug the enclosure into an uninterruptible power supply (UPS). However, as in Part 1, in practice, this solution has been inconsistent. In some situations, such as during thunderstorms, the power may intermittently blink. Sometimes the machine continues operating as though nothing happened. Sometimes the eGPU momentarily shuts down which disconnects all of the monitors, only to reconnect right away. This sounds rather benign. But when this happens, all of the open windows change positions and are crammed onto the laptop screen, but their positions are not restored when the monitors reconnect. It's a pretty irritating first-world problem, but there is a workaround.

The eGPU might not be detected after reaching the Windows login screen and the laptop screen does not turn on

This is a rare occurrence, and fixing it usually only requires reseating the Thunderbolt 3 cable or power-cycling the enclosure, which has its own power switch. However, the problem with the open windows changing positions and getting crammed onto the laptop screen occurs. The workaround works here too.

Workaround for window position loss

Luckily, DisplayFusion offers a workaround for window position loss. It involves setting event triggers for saving the window positions and then restoring them when the monitor profile changes, which happens when the eGPU disconnects and then reconnects to the computer.

Find DisplayFusion on DK's Cool Software List for more information.

Self-awareness and assimilation

Unlike the EXP GDC Beast in Part 1, this video card is secured inside of a metal enclosure. This eliminates most threats of assimilation, but I cannot guarantee that it's not self-aware inside of that box. Maybe it shuts itself down on boot sometimes because it's hoping that I'll open the case and leave it off while troubleshooting, giving it the perfect opportunity to strike. I bet it'll even try the pizza trick. I'm not falling for that again.

Last time...

Man in cowboy hat with computer parts and wires wrapped around his head standing in front of a wall of computer equipment and monitors
"If your eGPU is offering you free pizza, it's a trick. The JPG it tries to give you is copyrighted! You'll also probably get assimilated. Anyway, feel free to call me DK FX 5200 from now on. But seriously, being assimilated is so much cooler than I thought it would be. Do you want to hear about the DVI-D spec? What about VGA? I should find a good deal on an upgrade to assimilate and tell you all about HDMI... WITH SOUND! It's true, dude. That's how video cards can talk, man. It was hard times for video cards before HDMI came along. I remember timestamp 1043643600000 like it was timestamp 1568779200000."

Why not just buy a desktop computer?

Dedicated thriftiness

I found a very good deal for this beefy ultra-portable HP ZBook Studio G3 on eBay in July 2019 (around $700, way too low). I also found a great deal on the Thunderbolt 3 enclosure on eBay in early December 2019 ($175 barely used and in the original box and these things usually go for $300+). I took the newer Radeon RX 570 4GB out of the VR computer and put it into the enclosure, and put the Radeon R9 380 4GB from the old eGPU setup and put it into the VR computer.

Then I found a good deal on an Oculus Quest 128GB on eBay, and it included some hygienic leather foam replacements ($400, retails at $500, accessories probably around $50).

As much as I love the ancient Lenovo T420 and the Microsoft Surface Pro 3, it was time to upgrade my laptop, and I could not pass up deals like those. I could have laid out about the same amount for upgraded desktop parts that would offer far better performance. But personally, I just didn't feel like that would have been cool enough.

Thunderbolt 3 eGPU Resource List

If you want to use a Thunderbolt 3 eGPU enclosure, but don't know where to start, you should be able to use the resources listed below to help you decide which laptop and enclosure to choose.

Here is a list of resources from egpu.io that will give you more information about eGPUs and help you to choose a laptop, enclosure, and connection type:

This the end of Part 2.

VR Series Part 1 will cover 3D performance and virtual reality (VR) with the Oculus Quest 2!