I bought an i5/8GB/256GB Mac Mini a few days ago, and thanks to the Holiday return policy, I have till January to test it out and decide if I want to keep it. I ran some Cinebench synthetic benchmark and some practical tests on the 2018 Mini and thought it might help others trying to decide between the i5 and i7 (although it might end up confusing you guys even more

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Primary Usage: Lightroom and Photoshop Editing, Clean Audio Source
I currently use a 2012 2.3QC Mac Mini with 16 GB RAM and maxed out SSDs. The Mini also has one of the cleanest optical out ports which I connect to Schiit Audio Bifrost DAC and Sennheiser HD600 headphones. Unfortunately, the 2018 Mini has dropped the Optical Out (why Apple?) and I have ordered a Hifimediy USB to Mini Toslink converter to compare against the native Optical out of the 2012 Mini (more on this later)
Back to testing. Let's start off with the synthetic tests first.
Synthetic Benchmarks: Cinebench and Intel Power Gadget
- Ran Cinebench a couple of times, and the i5 Mini maintained a turbo of 3.9GHz easily with a score of 955 (Screenshot 1)
- Continued running Cinebench 2 more times, and turbo moved between 3.8 and 3.9 GHz resulting in a score of 948 (Screenshot 2)
- Continued Cinebench testing non-stop, this time the i5 turbo fell down to 3.7 Ghz resulting in a score of 921 (Screenshot 3)
Practical Test: Exporting 650 RAW Pictures (24 MP) to JPEG (90% compression)
The processor maintained a Turbo Boost of 3.9 Ghz throughout the Export Process. Temperatures were stable around 90C. (Screenshot 4)
Hope these tests help others perform a comparison with i7. Overall, the performance is quite solid. If you are looking to configure the i3 Quad core version with 256GB SSD, then it is a no-brainer to pay 100$ extra and get the i5 six core processor. Compared to my 2012 Mini, the fan on this model is quieter and has a lower pitch.
If anyone has additional tests that they would like to be done on the i5, let me know.