Beaten and battered by the Razer Core X‘s one-two punch, Mantiz had no choice but to move up in weight class with its newest contender. A chiseled heavyweight entering the ring with a chip on its shoulder, the Mantiz Saturn Pro follows in the foot steps of the Mantiz Venus with aluminum construction, clean aesthetics, and an all-in-one docking solution. At $299 it is a hard puncher with more power, more features, and more value than any other eGFX to date. This newest eGPU enclosure runs circles around the competition.
|PSU max power||750W|
|GPU max power
|Power delivery (PD)
|TB3 USB-C ports||1|
|Size (in/mm, LxWxH)
||14.7 x 6.6 x 9.1
374 x 168 x 232
|Max GPU len (in/cm)
|Updated firmware||44.44 ✔|
|TB3 cable length (cm)||70|
The Mantiz Saturn Pro is the second-generation eGPU enclosure from Mantiz. Its overall footprint has grown to accommodate a larger ATX power supply, more space for the graphics card, and better cooling. Thanks to these larger dimensions, it has much easier internal component access compared to the Mantiz Venus. The inner cage slides back once you remove the large thumb screw on top. On the rear fascia there are two stubby L-shaped hooks that provide grip. It’s an unusual design but works well so that a full handle doesn’t block the graphics card ports.
From most angles the Mantiz Saturn Pro is an attractive enclosure. Similar to the Mantiz Venus, it doesn’t sport any RGB. The design aesthetic is clean and professional to accompany modern Macs. The expansion port row on the front fascia is well-proportioned and provides quick access for SD card and USB-A peripherals. There are three anodized finishes to choose from: silver, space grey, and black. My sample unit came in space grey. The brushed aluminum has a defined texture that feels great to the touch. This finish hasn’t attracted many fingerprints during my two months of testing.
Build quality is one of the best of any external graphics boxes I’ve used. The outer shell is light yet rigid. Rather than using separate top and side panels, Mantiz formed a single aluminum sheet that is joined at the bottom with a thermoplastic base. It’s a neat design that incorporates a large rubber pad on one side and a plastic base on the other. The enclosure opening/sliding mechanism is very similar to the Razer Core X/Chroma; two plastic rails on the underside of the inner cage hook onto the plastic base inside the outer shell. This design works smoothly and requires no lubrication.
The Saturn Pro and Core X/Chroma share many design elements, but Mantiz outpunches Razer with its power supply. It’s an 80+ Gold 750W single-rail unit that provides 100W upstream Power Delivery and maximum 550W to the graphics card. This is the highest-output PSU in an eGPU enclosure, compared to the 650/700W multi-rail unit in the Core X/Chroma. With 3x 6+2-pin PCIe power cables, the Saturn Pro‘s power supply can handle even the most monstrous of graphics cards (Nvidia RTX 3090 & beyond). Other power cables are one 24-pin to the mainboard, one SATA for the hard drive, and one Molex for another component such as the fan controller.
By using a larger footprint Mantiz was able to fit two 120mm cooling fans inside the Saturn Pro. Installed on a metal bracket, they are stacked side by side with one being the PSU fan. The other 120mm fan draws heat from the back of the GPU outside. The enclosure fan bracket can be used for mounting a 120mm radiator in most AIO liquid-cooled GPUs. My RX 5700 XT with third-party liquid cooler fit perfectly but required a lot of cable management to avoid the fan blade. The PSU has a fan-off mode to keep things quiet during light use.
Other refinements are the metal shield on the Thunderbolt 3 mainboard and quick access to the SATA drive. The 2.5″ drive bracket sits on top of the enclosure cooling fan mount and can be removed. In my installation of an AIO liquid-cooled GPU, I had to remove the SSD bracket and relocate the drive to sit at the bottom in the space between the mainboard and front expansion board.
Improving on an already well-appointed offering (5x USB, 1x SATA, and 1x Ethernet in the Venus), Mantiz added an SD card reader and hosted all expansion I/O on a secondary Alpine Ridge Thunderbolt 3 controller. The Saturn Pro is the first and only enclosure to date to include an SD slot. This is a much welcome addition for Mac and ultrabook users. The dual Thunderbolt 3 controller design remedies I/O stability issues on first-generation eGPU enclosures. The only other port I wish the Saturn Pro had is USB-C.
The Thunderbolt 3 mainboard contains rear expansion ports rather than a separate rear daughterboard as in the Venus. Identical to other dual Thunderbolt 3 controller eGFXs, the Mantiz Saturn Pro has a primary Intel JHL6540 and a secondary Intel JHL6240. Also found on this board are the firmware Winbond EEPROM chips and Texas Instrument TPS65983BA USB-C controller.
The primary TB3 controller runs firmware version 44.1, and the secondary TB3 controller runs firmware version 20.1. Upstream Power Delivery is set at the maximum 100W to the host laptop. This PD rating allows the Mantiz Saturn Pro to charge all certified Thunderbolt 3 laptops, including the latest 2019 16-in MacBook Pro (96W). Other TB3 laptops I tested were the 2020 13-in MacBook Pro Ice Lake (61W), HP Spectre 13-in OLED (65W), LG Gram 17 (~70W).
There are two USB 3.0 buses that host expansion components: one on the daughterboard (SD card slot and 3x USB-A ports), the other on the mainboard (Ethernet, 2x USB-A ports, and SATA header). I installed a PNY CS1311 480GB 2.5″ SSD inside the enclosure. This hard drive has been in use for the past few years and doesn’t reach anywhere near the 520 MB/s max speed. The other peripherals are an Ethernet port connected to Ubiquiti switch, Logitech Unifying receiver for mouse & keyboard, and a Lexar Professional 1667x SDXC UHS-II 128GB card. All components worked immediately without the need for any third-party drivers.
In order to test stability during use I wanted to have multiple peripherals running. I ran AJA System Test on the SATA SSD, CL!ng on the WX 9100 eGPU, and Internet speed test on the Ethernet port simultaneously. This test lasted 10 minutes, and no issues were observed. Both the mouse and keyboard were responsive without lagging behavior. I also ran AJA System Test on the SD card reader. The Lexar 1667x V60 II card was able to reach near max speed of 250 MB/s. Theoretically all expansion I/O traffic through the secondary JHL6240 controller can use up to 10Gbps of the max 22Gbps bandwidth of a single Thunderbolt 3 connection.
Cooling performance of the Mantiz Saturn Pro has improved over the Venus. Airflow is now routed sideways rather than out the bottom. It’s also a better performer than the Core X/Chroma thanks to vents in the front fascia and a larger PSU fan (120mm vs 60mm). Unlike the constantly running PSU fan in most eGFXs, the Saturn Pro‘s power supply fan stays off during light usage.
All Thunderbolt 3 Macs running macOS 10.13.4 or newer work plug-and-play with the Mantiz Saturn Pro when using a modern Radeon card. Older Thunderbolt 1/2 Macs can work with Mac_editor‘s Purge-Wrangler script. Apple has made significant changes to macOS 11 Big Sur, so more work is needed to enable the eGPU feature on older Macs. I’ve been testing my 2013 Mac Pro with the Saturn Pro + RX 5700 XT eGPU. The dual FirePro dGPUs in this generation Mac Pro are prone to issues as they age, so using an eGPU not only improves the performance but also prolongs the computer life [build link].
Unfortunately eGPU support with Boot Camp has not improved. As a matter of fact, Apple’s switch to ARM CPU for their Mac lineup means Boot Camp mode will go away eventually. If you need Windows for gaming and/or work, it might be time to switch away from macOS. In order to get a Mac working with a Radeon eGPU in Windows, we almost always have to resolve error 12. Things become more complicated with the Apple T2 Security Chip. My testing in Windows connecting the Mantiz Saturn Pro with the LG Gram 17 and HP Spectre 13 OLED went much better than Boot Camp mode with a 2020 13-in MacBook Pro.
Using eGPU with Linux is also of great interest. My distro of choice is Pop!_OS by System76. Pop!_OS is based on Ubuntu which has very good Thunderbolt hot-plug support. Members in our community have shared different solutions to facilitate graphics switching in Linux. Thanks to Proton and Steam Play, we can now play many Windows titles in Linux with ease. I tried The Witcher III on the HP Spectre 13 + Mantiz Saturn Pro + RX 5700 XT eGPU setup [build link]. The installation process and gaming experience was similar compared to Windows.
Priced to be the most affordable full-featured eGPU enclosure on the market, the Mantiz Saturn Pro delivers a knockout punch in performance and value. It showcases the best of the four-year evolution of Thunderbolt 3 eGPU technology. With a unique combination of good looks, unrivaled expansion ports, and exceptional flexibility, the Saturn Pro is truly king of the ring.
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