Both processors were pretty terrible when they came out and haven't aged well. The N3540 has 4 cores 4 threads with a higher clock speed but an older architecture meaning it'll perform very slightly worse than the i3 which has 2 cores and 4 threads.
Also, don't use userbenchmark for performance comparisons, it's terrible and woefully inaccurate for pretty much every measure.
With maxxed out memory they'll both perform well enough for light tasks like web browsing or office work, especially since you've noted you've moved to using Linux. Neither will run particularly well with a modern iteration of Windows.
