OP - Checkout some Z3580 benches here -
http://www.notebookcheck.net/Intel-Atom-Z3580-SoC.123974.0.html
I also have a Baytaill based Z3735D SOC in my tablet, but it's slower than the Z3580 in a couple ways.
I believe they share the same CPU architecture, but Moorefield has dual channel ram vs. single channel found on Baytrail. Moorefield also has higher boost frequencies.
Baytrail also has the slower Intel HD Gen 7 GPU, while Moorefield has the faster PowerVR G6430, like found in the iPad Air/5s, albeit with faster clock speeds thanks to the smaller process node (22nm vs. 28nm).
So to make a direct comparison would be tough.