One of the first tests of a Gemini Lake product, the Asrock J4105-ITX, which is equipped with a Celeron J4105:
Link (translated from german)
The performance increase from Apollo Lake is pretty massive in Cinebench R15, which is the only test they ran:
OpenGL: 21.19 FPS
ST: 73
MT: 263
Compare this to my own tests of the Apollo Lake (Pentium J4205) based Asrock J4205-ITX, which I posted in this thread in November 2016:
OpenGL: 21.57 FPS
ST: 52
MT 193
The CPU part of the Gemini Lake Celeron is ~40% faster than the Apollo Lake Pentium! It's also interesting that power consumption does not appear to have increased, at least on the system level. From what I can gather this is slightly better than the venerable old Core 2 Quad Q6600 @ stock. Given that they both run at basically the same frequencies, it seems Goldmont Plus has slightly better IPC than Conroe/Kentsfield. Obviously with the help from much faster RAM than what was available at the time, but still. More results are needed, but this architecture seems pretty impressive.
EDIT: My old tests can be seen
here.
I'm really tempted to get the NUC7PJYH with the Pentium J5005. Should be a pretty awesome NUC for media and emulation. The native HDMI 2.0 should solve a lot of the problems people had with display output.
Out of pure academic interest, it would be interesting to see how Gemini Lake compares to modern ARM chips in terms of performance and power consumption. My guess is that performance is comparable to the latest high-end offerings (excluding Apple...), but the power consumption comparison is harder to guess the outcome of.