Idiot Savant

Idiot Savant is a perk in Fallout 4.

Effects
This perk will randomly multiply the amount of experience gained from any action that grants experience, including quest completions, making it very useful to grab at a low level so that you can maximize the amount of extra experience gained. The effect is multiplicative with the well rested bonus giving a total multiplier of 3.3 or 5.5 depending on the rank of the skill. The effect is also multiplicative with the additional experience gain resulting from having points a higher intelligence.

When the perk activates, you will see a laughing Vault-Boy above your compass, as well as hearing a laughing sound.

Despite reports from other sources, once you obtain the second rank of the perk, it grants a 5x experience bonus every single time the perk activates. There is no tiered check that determines whether 5x experience is granted, then whether 3x experience is granted.

For Intelligence of 1, this perk has a 10% of being triggered. This percentage decreases by 1% per point of Intelligence for a minimum chance of 1% when Intelligence is at 10. At 6 Intelligence, the chance of triggering the perk is 5%.

In order to maximize the effects of this perk, make sure to get it as soon as it's available, especially for the first two ranks. You may also save the game just before turning in a quest and keep reloading until the perk activates upon quest completion to get large amounts of experience. At lower levels, the perk activating upon quest completion grants at least half a level's worth of experience. As an example, once I turned in the second Brotherhood of Steel quest (the first quest that the scribe at the Cambridge Police Station gives you), I leveled up (I only needed a little bit of experience to level), but my next level got filled about 90%. If you do use the reload method, make sure that you're Intelligence isn't too high or it will take many attempts to trigger the perk. I would say an Intelligence of 5 or 6 should be highest to obtain while still having a reasonable chance of triggering the perk (6% or 5% respectively).