I recently found a Relic slot item that says "Use: Increases Critical Rating and Surge Rating by 50 for 20 seconds."
Critical Rating deals with Critical Hits, but what is Surge Rating?
I recently found a Relic slot item that says "Use: Increases Critical Rating and Surge Rating by 50 for 20 seconds."
Critical Rating deals with Critical Hits, but what is Surge Rating?
Both of them are related to critical hits. Critical Rating affects how often do you make them, Surge Rating affects how much damage do they deal if you make them.
For details, hover over Critical Chance and Critical Multiplier on your character sheet: