[vardump]

The chart seems to indicate about 25 GFLOPS for sequential performance, while real value is up to 100 GFLOPS theoretical at 3.1 GHz on Haswell/Broadwell on a single core.

While realistic single core performance won't of course be approaching 100 GFLOPS, 25 is a pretty lowball value.

[wtallis]

Is it possible that they're using "sequential" strictly, to mean that the arithmetic isn't vectorized? What's the scalar throughput like?

[vardump]

Scalar output would be way less than that number, 25 GFLOPS. At most 2x clock frequency. It's likely their benchmark just doesn't support AVX2 (and FMA [1]).

You get about 25 GFLOPS if you use SSE only.

[1]: https://en.wikipedia.org/wiki/FMA_instruction_set