The Z3580 is a lower binning Pentium.
The clock is lower for the CPU and iGPU but so is the wattage (just over half) so great battery run time.
This model Atom has both memory channels working so it runs 64 bit Windows, while the Z3735F in my X205TA has only one channel which can support 2 GB runs 32 bit Win.
The older Atom series like in my netbook LT4004u with N2600 is a different animal but with a six cell battery has decent run time but not when compared to my ASUS X205TA
BTW that old netbook which came with 1 GB mem was slow but the recommended swap to 2 GB sped it up. But after I upgraded 7 home premium I decided to see what would happen if I tried a 4 GB stick even though 3 GB was the max 32 win would support. It gave a big boost to perf over all but that reserved 1 GB gave a little more memory to the iGPU so the win experience number increased .2 for graphics.