If your on a mechanical HDD, having blazing fast ram won't help your speeds. Loading times will stay the same, as will boot-times.
If your on an SSD, faster ram may allow you to see a marginal improvement.
If you, however, have alot of RAM partitioned as a temporary game/application storage space, you'll see a more reasonable improvement.
Don't see why you'll want 2000 MHZ Ram, anyway. Just get a few sticks of good 1600MHZ Ram, and you'll be fine.