B&H Photo loaned MPG the latest top-end MacBook with 1.3 GHz processor, 8GB memory, 512GB PCIe flash drive along with a USB-C to USB adapter (even better: Apple USB-C Digital AV Multiport Adapter and most users will want both).
My review of the 2015 MacBook is now published with multiple performance evaluations, mostly real-world assessments (stuff that I actually do daily):
- 2015 Apple MacBook: SSD / Flash Drive vs 2015 MacBook Pro Retina
- 2015 Apple MacBook: IntegrityChecker Verify Hashes
- 2015 Apple MacBook: Photoshop Benchmarks
- 2015 Apple MacBook: Real-World Photoshop Work
These tests add a perspective by including the 2015 MacBook Pro Retina.
...In general, the 2015 MacBook is a fine performer in the context of its turtle-slow clock speed of 1.3 GHz—underpowered but runs like a champ given the “engine” that it has to work with.
SSD / flash drive speed shown below; see all the review pages for details and more.