UnitHealth refresh

[doofus]

Every so often, sometimes as often as 3-4 times a second, I call UnitHealth(), and it seems it is "slow" to update, whereas the standard Blizzard raid frames are much more responsive. Looking at gamepedia it seems there used to be a UNIT_HEALTH_FREQUENT event that was remoived with 9.0.1 - but the point is that somehow the standard Blizz party/raid frames work very responsively.

Are there other API calls to retrieve the latest HP of a unit that I should be using?