2018 was a breakout year for external graphics card solutions. Intel and Thunderbolt partners introduced almost a dozen of eGFXs. Apple also participated by way of their collaboration with Blackmagic Design. Lost in the media frenzy was the Sapphire GearBox Thunderbolt 3 eGPU enclosure. Our forum members had spotted this enclosure at Computex 2017. The retail offering was slow to follow. Sapphire officially announced the GearBox on November 30th, 2018 with MSRP of $339. The price has since dropped to $259.
Over the past month I’ve thoroughly tested the Sapphire GearBox. It’s a full-length eGPU enclosure with a compact footprint, useful expansion ports, 60W Power Delivery, and 300W max graphics card output. The problem is this eGFX was ready to go more than a year ago and should have been released then. For unknown reasons Sapphire put it on the back burner until now. As of 2019, usability issues such as loud PSU fans and half H2D speed are not acceptable.
|PSU max power||500W|
|GPU max power
|Power delivery (PD)
|TB3 USB-C ports||1|
|Max GPU len (in/cm)
|Updated firmware||26.26 ✔|
|TB3 cable length (cm)||50|
The front fascia is unfortunate. It’s worse when the blue lightbar is on which is all the time when using the GearBox. Even when you put the host computer to sleep mode this lightbar stays lit, going into pulsating mode. Then there’s the large Power button. There’s already a power switch in the rear on the power supply. You need to hit two Power buttons to turn on the enclosure. Many a time I forgot to push the front button and thought something was wrong.
Rear expansion I/O consists of two USB 3.0 ports and one Ethernet port. As seen in the component layout photo below, the Ethernet port is on-board next to the upstream Thunderbolt 3 port, while the two USB ports are on an extension cable connected to a blue USB header. This enclosure is well-built and main panels are made of aluminum. Component arrangement makes things very serviceable. I have not tried yet, but it seems possible to mount a radiator to the top vents.
Unfortunately it’s a convoluted process to swap the graphics card. The Sapphire GearBox comes with a hex wrench for this sole purpose. There are four hex screws locking the top cover to the bottom platform. Two of them are mounted in the top rear and the others are towards the bottom of the side panels. Once the screws are out of the way, you can lift the top cover up and pivot it forward. The top shell can rest on the front fascia but remains connected to the bottom platform at the front hinges. There are four cables running from the main board to the power button, lightbar, and two 120mm cooling fans through the hinges.
Inside there are many similarities between the Sapphire GearBox and the original Razer Core. The power supply placement is identical by sitting vertically inside the enclosure and parallel to the graphics card. As a matter of fact, the PSU is the very same Enhance model, ENH-2350. This power supply is a 12V single rail 500W unit. It has two 6+2-pin PCIe power cables for the graphics card, one 24-pin ATX cable, and one 8 EPS cable for the Thunderbolt 3 mainboard.
Using a flex ATX power supply means tiny 40mm cooling fans. These fans omit a high-pitch noise all the time. During idle and even in sleep mode, my sound meter registered 48 dB when placed near the rear vents of the Sapphire GearBox. You read that right, the PSU fans don’t stop running even when the enclosure is in sleep mode. From past exchanges with TB3 vendors, eGFX with Power Delivery may run the fans when the computer is asleep to regulate airflow. A positive aspect of the cooling system is the pair of 120mm fans mounted on the underside of the top cover. These two fans draw heat from both the PSU and installed GPU up and out through the top vents. They are inaudible compared to the PSU’s and GPU’s fans.
The Thunderbolt 3 mainboard has a few interesting components not seen in other TB3 eGPU enclosures. There’s a red reset button. During my testing, I did not need to use this button at all. This mainboard also has a standard blue USB 3.0 header. It’s possible for modifications to route expansion ports elsewhere rather than the rear. Next to this header is an 8-pin EPS plug, and a 24-pin ATX plug. Last but not least are the three crucial ICs, located near the Thunderbolt 3 port. The usual suspects are the Texas Instrument [TPS65983] USB-C controller, Intel Alpine Ridge [JHL6540] Thunderbolt 3 controller, and Winbond EEPROM firmware memory chip.
One usability issue I noticed during GPU removal is that it’s impossible to release an installed GPU by hand. Due to the minimal gaps between the GPU and PSU as well as the mainboard, I could only access the PCIe slot release tab with a flat head screw driver. Also to note is the limited length of this enclosure. While I was able to fit the Radeon RX Vega 56 reference GPU, this is about as long a graphics card that the Sapphire GearBox can fit. There’s absolutely no more room for longer cards. Height and width have plenty more room to accommodate stubbier-shaped GPUs.
Testings & Benchmarks
My first test was with a 2018 13″ MacBook Pro. The Power tree in System Information confirmed Power Delivery is 60W. It’s a convenient feature to charge a Thunderbolt 3 laptop while it’s connected to the eGPU, all through one single Thunderbolt 3 connection. This amount is sufficient to charge the majority of ultrabooks on the market. Another check I did was Thunderbolt firmware version. The retail version of the Sapphire GearBox came with version 26.26. The newest version I’ve seen is 35.1, but Intel doesn’t make upgrading the firmware easy or widely accessible.
Sapphire tuned the GearBox firmware to limit the host-to-device (H2D) bandwidth at half speed. This is a tweak to provide a balance between eGPU and expansion port performance. As seen in CL!ng screen captures below, the Paged Host to Device reading is at 1,129.54 MiB/s rather than 2,577.92 MiB/s in the ASUS XG Station Pro. The max Thunderbolt 3 enclosure bandwidth is already capped at 22Gbps (not 40Gbps) so we certainly don’t want any more throttling. The tradeoff as claimed is stability for low-latency peripherals connected to the USB ports during heavy eGPU load.
The Sapphire GearBox is certified on both Windows and macOS. Staring with macOS 10.13.4, native eGPU support is reserved only for Thunderbolt 3 Macs with select AMD Radeon graphics cards. Nvidia eGPU and older Macs don’t have support from Apple. Our community has active developers who have engineered workarounds. Mac_editor wrote a script to unblock Thunderbolt 1 and Thunderbolt 2 Macs for eGPU access. Goalque built an EFI boot manger that enables Nvidia and older AMD graphics cards for external use. Due to no compatible Nvidia web drivers in Mojave, we are currently limited to GTX 700 series and older Nvidia GPUs which have macOS drivers.
In Windows 10, there are more graphics card choices and better gaming performance. The setup process for Macs is not as straightforward as Windows computers. I used the 2018 Mac mini for testing in Boot Camp. It is less troublesome compared to other Macs due to iGPU-only and no attached display. A setup process I found works consistently is completing Windows installation and Boot Camp drivers then hot-plugging the eGPU. Windows 10 detects the eGPU and installs the graphics drivers automatically. It’s advisable to download the latest graphics drivers from AMD or Nvidia manually to get the best support for newest games.
Once the graphics driver installation is done shut the Mac mini down and switch the monitor output from the HDMI port to one of the monitor output ports of the eGPU. This is necessary because the presence of an eGPU at boot disables the Intel iGPU (no monitor output through the Mac mini’s HDMI port). There are ways to keep the Intel iGPU activated during Windows boot up with an eGPU connected. It involves third-party boot managers such as rEFInd, apple_set_os.efi, or automate-eGPU EFI by Goalque.
To run a set of synthetic benchmarks I paired this Sapphire GearBox eGPU enclosure with the RX Vega 56 (flashed with RX Vega 64 vBIOS). The host computers are the 2018 Mac mini i3 base configuration. I ran it through internal Intel UHD iGPU first for a baseline then eGPU through the HP Z27q 5K monitor. Boot Camp mode was running Windows 10 Fall Update (1809) and latest Radeon drivers. It’s worth noting the 2018 Mac mini has the dual Thunderbolt 3 controllers attached directly to the CPU. This Thunderbolt 3 connection routing is superior to systems that have their Thunderbolt 3 ports going through the PCH.
|2018 Mac mini i3||UHD 630 iGPU FHD||Vega 56 eGPU FHD||Vega 56 eGPU QHD||Vega 56 eGPU 4K||Vega 56 eGPU 5K|
|Tomb Raider 2013||8.4 FPS||126.0 FPS||94.4 FPS||49.9 FPS||29.2 FPS|
|Shadow of Mordor||9.3 FPS||102.8 FPS||84.3 FPS||49.5 FPS||30.7 FPS|
|Dirt Rally||12.5 FPS||58.3 FPS||51.3 FPS||39.3 FPS||34.4 FPS|
|Hitman||13.9 FPS||80.3 FPS||76.9 FPS||59.6 FPS||39.0 FPS|
Like an old manual transmission, the Sapphire GearBox is loud and clunky to operate. But unlike having the control of the driver’s seat, using this eGPU enclosure feels more like riding a semi for public transportation. At $259, the GearBox Thunderbolt 3 eGPU enclosure is a good value but there are further refinements for Sapphire Technology to consider. First is to provide firmware options to either prioritize expansion port stability or maximize external GPU performance. The second improvement is PSU fan-stop in sleep mode. We hope 2019 will be a year full of refined, affordable and user-friendly external graphics solutions.