People have different notions about this, so let me share the secret sauce:
vRealize Operations Manager Out of the Box, is configured to collect data every 5 (FIVE) minutes form the source. The collector wakes up every 5 minutes and gets last 15 samples of 20 seconds interval from the source.
15 Data Points X 20 Seconds = 300 Seconds ( 5 minute collection cycle)
As we all know you can further transform this data in views and super metrics by using functions such as Min, Max, Standard Deviation etc. All these functions run on the data saved in FSDB which is the 5 minute data point explained above.
These transformations are NOT ran on the 20 seconds samples. The 20 seconds samples infact are used to do calculations of the 5 minutes data points and are dropped as soon as that calculation is done. This reduces the storage requirement drastically.
Also, it is possible to change this default collection cycle from 5 minutes down to 1 minute, however it is not recommended to do that unless you understand the overall impact on Compute and Storage for increased collection and processinh.
Hope this helps!!