Guinsoo's Rageblade is 75% statistically efficient with no stacks. Its stat efficiency increases by 8% per stack, becoming efficient by the fourth stack and reaching 138.7% stat efficiency at maximum stacks.
Alternatively, the item becomes 129.6% efficient while the user activates the passive at less than 50% health.
With all passives at their maximum value, the item becomes 193.5% efficient.
The unique passive ends after 10 seconds of neither dealing nor receiving damage.
Multiple Guinsoo's Rageblades will give multiple stacks for each autoattack and ability cast, but a champion can still only have eight stacks in total.
Guinsoo's Rageblade's unique combination of traits make it something of a niche item. It is best on autoattack-based champions who benefit from both attack damage and ability power (Jax), especially those who profit from being low on health (Aatrox, Tryndamere, and Poppy).
Guinsoo's Rageblade was one of the last items released before the launch of League of Legends itself.
The icon for the unique passive's buff is the same as that of the removed summoner spellSurge. Additionally, the two share the same visual and audio effects.
There once existed a bug that enabled Sion to attain negative ability power and maximum attack speed with Guinsoo's Rageblade alone.
When fully stacked, and its secondary (surge) passive activated, Guinsoo's Rageblade gives the third highest attack speed bonus (52%) in the game of all Items, behind Sword of the Divine (100% when activated) and Runaan's Hurricane (70%).