Results of chrome.system.memory and chrome.system.cpu APIs

[Sruti Bhagavatula]

I am building a Chrome extension which tracks computer CPU usage and memory usage at intervals. 

I am able to calculate the overall CPU usage % by using the chrome.system.processes API and the results seem consistent enough with my actual system reports.

However, to get memory usage, I am using chrome.systems.memory. I compute current memory usage as (capcacity-availableCapacity)/capacity. This number is always extremely high around 91% of the total 16GB on my machine when the activity manager on my machine shows a much lower usage. Does this API return an accurate value of RAM usage?

Thanks a lot!