With many players reaching endgame and finishing farming stats for their Cloak of Infinite Potential, it is a good time to highlight the limits of the rating system in WoW to help you maximize your character's stats.
These limitations were added in Shadowlands when Blizzard added diminishing returns to stats to diversify itemization at the end of expansions. You can read more details about how that system works in our guide:
Stat Diminishing Returns in World of Warcraft
These limits are the end stage of the Diminishing Return system.
*Mastery is a unique stat, and the cap is 126 Mastery Points instead of 126%. You can read more about how mastery works here
The cap means you can't benefit more from their specific rating once you reach that value. You can still increase it with effects that give flat percentages. For instance, even while receiving 126% haste from rating, you still gain more haste with Bloodlust/Heroism, or even at 49% leech from rating you can still increase it by the base effect from Vampiric Aura (Party bonus is a rating increase, thus won't work for them).
With that in mind, here is amount of rating required to reach the 126% stat cap for each secondary stat:
Secondary Stat Caps
And here is the rating required to reach 49% in each tertiary stat:
Tertiary Stat Caps
After you reach a cap for a stat, either from Prismatic Gems or from your Cloak alone, you can swap gems around for other stats, either other secondary or tertiary, or even go full Perfect Stalwart Pearl for extra Armor for soloing content. Or you can just have the gems in your gear for the stamina benefit and not worry about