Free ram on the iPhone 6S?

HI,

i am using an iPhone 6S and using an app called iMonitor from the AppStore, to monitor the amount of free ram on my device. Usually after a fresh reboot, I get 750MB of ram free, and after some normal usage, I get 400MB when all apps are closed. Is this normal? How much free ram should a 6S have normally? Please share your ram data. Please use the iMonitor app to get ram readings, as I found that different apps show different results. It's free on the AppStore. Also, how long do the 6S take to turn on after being powered off? Mine take about 18-20 second.