Review of Macs' eGPU support, new with macOS 10.13.4: performance gains are decent, especially for Metal, but support is limited to Thunderbolt 3 and AMD cards
Performance doesn't disappoint, but lack of strong software support does. — When Apple released macOS High Sierra 10.13.4 on March 29 …
Context & Ripple Effects
This review lands one step into an arc that started with the High Sierra review calling macOS catch-up mode on external GPUs, which Windows machines had supported for years. Apple then published its own compatibility guidance in 10.13.4, recommending specific enclosures and AMD cards while listing no Nvidia options, and this piece is the first real performance verdict on whether that officially sanctioned path delivers.
The verdict matters because it defines what Mac graphics expansion looks like under Apple's rules: real gains where Metal is used, but a hardware whitelist that excludes Nvidia entirely. The later Apple-sanctioned Blackmagic eGPU — a sealed box with a fixed mid-range Radeon Pro 580 and no upgrade option — shows where that curation heads next.
First-order effects
- Owners of Thunderbolt 3 Macs can now buy an enclosure plus an AMD card and see decent gains, but only in apps built for Metal — general software support is the weak point, so most buyers' everyday apps see little benefit.
- Nvidia card owners are locked out entirely: Apple's support list names no Nvidia GPUs, so the installed base of high-end Nvidia cards has no sanctioned route into a Mac.
Second-order effects
- Enclosure makers and AMD gain a new Apple-endorsed sales channel, while Nvidia is pushed out of the Mac upgrade market unless Apple changes its list — making AMD the default supplier of Mac external graphics.
- Vendors have an incentive to chase Apple's blessing rather than open compatibility, a path the Blackmagic eGPU follows by shipping a non-upgradable mid-range GPU in exchange for easy setup.
Third-order effects
- If the pattern holds, Mac graphics expansion becomes a curated accessory market — Apple decides which enclosures, cards, and APIs qualify — rather than the open upgrade path PC users expect, with Metal acting as the software gate.
- Developers face pressure to target Metal specifically to reach eGPU-equipped Macs, reinforcing Apple's own graphics API at the expense of cross-platform paths like the DirectX-oriented workflows virtualization tools such as Parallels later had to translate.
The trend: Apple is converting external GPU support from an open PC-style upgrade path into a curated, Apple-gated accessory ecosystem built on Thunderbolt 3, AMD silicon, and Metal.