> Ubuntu used 500MB less than Windows in system monitor.

Those number meant nothing comparing across OS. Depends on how they counts shared memory and how aggressive it cache, they can feel very different.

The realistic benchmark would be open two large applications (e.g. chrome + firefox with youtube and facebook - to jack up the memory usage), switch between them, and see how it response switching different tasks.

Thanks for the critiques and the tips. I might try that in future testing.