After four years of neglect, the Mac mini returned to the spotlight in late 2018. The miniature headless Mac hasn’t fared well, now taking on a gray pallor and running a fever. Its Intel 8th generation 65W processor is an internal flame the cooling system can barely manage. Some may say the lack of discrete graphics is the final death knell. At eGPU.io we think this may be a blessing in disguise.
The other redeeming feature this 2018 Mac mini brings is what makes it a capable host for external graphics. Apple system designers connected a pair of Titan Ridge [JHL7540] Thunderbolt 3 controllers directly to the CPU with dedicated 4 PCI Express lanes each. High-performance Thunderbolt 3 devices such as an external graphics card do not have to share PCIe bandwidth with any other peripherals.
The 2018 Mac mini comes in two configurations, three processor choices, and lots of big money upgrades. The base configuration has an i3-8100b quad-core processor, 2x 4GB RAM modules, and 128GB PCIe NVMe flash storage. Priced at $799, it’s a whopping 60% price hike over the last generation Mac mini base model. It gets worse with the higher configuration. At $1,099 you get a Mac mini with a hex-core i5-8500b, 2x 4GB RAM modules, and 256GB PCIe NVMe flash storage. The 6-core, 12-thread i7-8700b is the most desirable option and only available build-to-order. Another BTO feature is the 10Gigabit Ethernet port for $100. Maxing out a Mac mini would cost you $4,199 [i7 CPU + 64GB RAM + 2TB SSD + 10GbE].
Compared to the 2014 Mac mini that had two Thunderbolt 2 ports, the four Thunderbolt 3 ports are the only added value in the 2018 Mac mini. Apple removed two USB-A ports, SD card reader, and Audio IN jack. One much-requested change in this new Mac mini is the RAM slots. We can now replace the RAM modules unlike the soldered RAM in the previous iteration. Unfortunately this is the only upgradable internal component because CPU and NVMe SSD are soldered to the logic board. Expansion capabilities are possible externally through the Thunderbolt 3 ports.
One new component that has made its way into all 2018 Macs is the Apple T2 Security Chip. It’s a co-processor that runs the Mac subsystem. Apple touted the T2 chip provides better security and a new level of integration. It handles the SMC, internal SSD encryption, audio and image controllers as well as Touch ID in compatible models. However there are concerns regarding ecosystem lockdown once all Macs are equipped with the Apple T2 chip. For example, this gatekeeper prevents our community eGPU solutions for older Macs, Nvidia graphics cards, and Boot Camp. There are also stability issues with Bridge OS that lead to random reboot and forced Recovery boot.
For thermal management Apple used a more substantial cooling system compared to previous Mac minis. Intake is through the circular gap between the plastic bottom cover and metal bottom shield. A single blower fan exhausts hot air through the vents on top of the rear ports. From my and others’ observations, it’s not effective enough for the i5 and i7 configurations. Due to thermal throttling additional cooling solutions would be needed to sustain maximum performance. One of our forum members @Sebastian presented a fun and effective DIY solution, aptly named Glory Blow Hole.
I ran the Mac mini vertically without the plastic bottom cover to help airflow. After testing the i5, I needed to exchange it for the i3 configuration because of overheating. The lack of discrete graphics is partially due to this design’s limited thermal envelope. If Apple were to implement an Intel Kaby Lake-G that combines an AMD dGPU, this cooling system would not able to keep up. The Intel UHD 630 integrated graphics card can power up to three 4K displays. Don’t expect it to do much more though. One HDMI 1.4 stream is wired to the HDMI port, while the two DisplayPort streams are routed through the Thunderbolt 3 controllers to dynamically handle two 4K monitors or one 5K monitor.
The only worthwhile custom option in the 2018 Mac mini is 10Gigabit Ethernet at $100. This 10GbE port is beneficial for accessing high-performance NAS. This alleviates the biggest pain point of the Mac mini, the internal soldered flash drive. Storage is the most over-priced to option through Apple. At 22 Gbps external Thunderbolt 3 NVMe SSD yields very close performance to the internal flash drive. USB-C 3.1 gen 2 is another external storage option that’s more affordable than Thunderbolt 3, but is limited at 10Gbps speed and taxes the CPU. From a service provider perspective, I have serious concerns about the lack of solutions for data recovery.
The best feature of this 2018 Mac mini is its dual Titan Ridge controllers and four Thunderbolt 3 ports. They allow external access to PCIe components. This was Apple’s intention all along because these Thunderbolt 3 controllers have direct access to the processor. This routing is superior to the most common Thunderbolt 3 connection where the TB3 port goes through the Platform Controller Hub prior to accessing the CPU. It bypasses the PCH which shares bandwidth with other internal PCI components such as NVMe SSD, Wireless card, and 1GbE card.
I wish Apple had gone the extra mile and leveraged the USB-C Power Delivery feature. It would have been a first in mainstream desktop computers. This innovative approach would make the 2018 Mac mini a headless Mac portable that uses a small battery to store system settings then draws up to 100W from an external power adapter or enclosure when it’s running. Instead Apple took the safe approach by using an internal 150W power supply (12V 12.5A). This PSU takes up nearly 25% internal space of the Mac mini which could be repurposed for better cooling or a smaller footprint.
Outside the Box
I like headless Macs. Throughout the past two decades these desktops have fallen into a cycle of hits and misses from the PowerMac G4 Cube to the Mac Pro tower and from the Mac mini to the trashcan. The key to whether a Mac desktop can succeed is its upgrade path. While you can swap almost all components of the G4 Cube and Mac Pro trashcan, there are little to no third-party parts available. First-party parts are either expensive or old as dirt when they become available.
The Mac Pro tower in a classic desktop form can accommodate all kinds of third-party components through its four internal PCIe slots. It remains relevant for hardware upgrades seven years after discontinuation. Recent firmware updates to the Mac Pro 5,1 allows NVMe M.2 solid state drive to be used as boot volume. Nvidia RTX graphics cards somehow come with UDA alternate vBIOS to provide boot screen for the Mac Pro towers. One of the more outlandish eGPU builds I put together in 2018 involved adding Thunderbolt 3 (Titan Ridge AIC) to the Mac Pro 5,1.
The 2018 Mac mini has this same potential with third-party component upgrades externally through its four Thunderbolt 3 ports. While they are capped at x4 PCIe 3.0 connection, many PCIe components don’t saturate this amount of bandwidth. External GPU and NVMe SSD are the exception. One of the more unique Thunderbolt 3 expansion enclosures is the AKiTiO Node Duo. As the name implies it has dual PCIe slots. In my review of this AKiTiO enclosure, I paired a whole mix of PCIe components alongside the eGPU. The upgrades this 2018 Mac mini needs the most are a high-capacity NVMe drive and a powerful graphics card. Well, it’s a match made in heaven when I set the Mac mini on top of the Node Duo. It’s as if this is now a Mac mini Pro with PCIe slots accessible through Thunderbolt 3 ports. Instead of spending an extra $600-$800 to configure a Mac mini with 1TB internal storage, I was able to get an RX 580 eGPU (~$200), 1TB NVMe SSD (~$150), and TB3 enclosure (~$350) for roughly the same cost.
It doesn’t stop there. The four Thunderbolt 3 ports can allow many more upgrades. A Thunderbolt 3 audio interface such as Universal Audio Arrow is an example. If your Mac mini didn’t come with 10GbE port, you can always get a PCIe 10GbE card and achieve the same result. Last but not least is Thunderbolt 3 monitor output for LG UltraFine 5K owners. I tested this theory by using a Gigabyte Alpine-Ridge Thunderbolt 3 add-in card to feed a pair of DisplayPort streams into the AIC then power a 5K monitor through a single Thunderbolt 3 cable.
During the past three months of using the Mac mini, I have paired it with different eGPU configurations. For multiple high-resolution monitor setups, a VisionTek mini eGFX + Radeon WX 4100 is a perfect match. For general purpose use in macOS and gaming in Windows Boot Camp, a Razer Core + RX Vega 56 is the best value setup in my opinion. A Mantiz Venus + WX 9100 would make the best eGPU for a Mac user if money was no issue.
Coined by Steve Jobs when he introduced the first generation Mac mini, BYODKM concept grows longer for the 2018 Mac mini. Bring-your-own sounds fun until you realize you don’t have the missing ingredients, and it’s going to cost you to make it whole. While the computer only needs you to provide a display, keyboard, and mouse, it begs for reenforcement with an external drive and discrete graphics card. People don’t have spare external SSDs and eGPUs lying around wishing for the arrival of a misfit such as this Mac mini.
The original concept worked because the target audience was switchers, who often already had their own display, keyboard, and mouse. Also Apple priced the first Mac mini at around $500 to be competitive with Windows PC counterparts of the time. In 2018 this landscape has shifted tremendously. With an $800 budget, you can build your own small form factor computer with capable specs. AMD Ryzen APU is an excellent choice. Intel NUC is another good platform that provides strong bones for a very portable computer. You may argue they don’t have two Thunderbolt 3 controllers and four ports like the Mac mini. However they may not need that much Thunderbolt 3 capability because they’re flexible enough for internal upgrades. As a proof of concept, I installed a Gigabyte TITAN-RIDGE add-in card to my Ryzen 5 2400G mini-ITX computer. This Thunderbolt 3 controller ignores the fact that the CPU isn’t Intel and works well with TB3 devices. It’s time for Intel to unleash Thunderbolt 3.
The Mac mini started life as a switcher Mac. This isn’t the case anymore. You’re no longer buying the Mac mini because it’s the most affordable option. You’re buying it because it’s the most flexible choice for third-party upgrades. Thunderbolt 3 technology is a welcome addition, and this headless Mac is certainly a capable eGPU host. However, the onus is on the consumer to invest the additional time and money needed to make it a complete system. Ultimately Apple’s renovation attempt fell short with a steep price hike.
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