Overclocked Monkeys gain a small but permanent boost each time Overclock wears off.
~ BTD6 description

Ultraboost is the 5th upgrade on Path 2 for the Engineer Monkey. It adds a 6.67% permanent attack speed boost to the overclocked tower after the ability is applied to the tower. This special attack speed bonus can stack additively up to 10 times, and grant 66% attack speed to the target monkey when maximized. Boosting a tower with both Overclock and the direct temporary Ultraboost boost will not stack with each other, but will be able to overlap each other.

When an Ultraboost is applied to the Monkey Village, the Monkey Village instead gains a 2.5% range buff per ability expiration, up to 25% permanent range increase. For Banana Farms, they will produce +66% more bananas per round, with +6.67% more bananas per permanent boost (up to +66% permanent boost).

It costs $102,000 on Easy and $120,000 on Medium, $129,600 on Hard, $144,000 on Impoppable.


Ultraboost equips the Engineer Monkey with a high-tech visor and an electricity-powered resource generator on his back. Similar to Overclock, the nailgun is actually a technologically advanced gun connected to his carryable generator. The Engineer no longer wears a pencil on his ear, but instead wears ear protection that comes from his high-tech visor.

Ultraboost abilityEdit

The Ultraboost's Overclock ability and a normal Overclock ability cannot stack despite being depicted in the tower buffs when selecting the tower. The visual effect is the ability applied later.

Besides an additional permanent attack speed boost provided from an expired Ultraboost (plus additional extra range for Monkey Villages), similar rules regarding the Ultraboost's Overclock ability are the same as regular Overclock:

  • Overclocked monkeys gain 66% attack speed.
  • Overclocked Monkey Villages gain 25% range during the Overclock boost.
  • Overclocked monkeys valued from $0-$15000 will be Overclocked for 60 seconds.
  • Overclocked monkeys valued at $15,001-$40,000 will be Overclocked for 45 seconds.
  • Overclocked monkeys valued at $40,001+ will be Overclocked for 30 seconds.
  • Banana Farms double income production during the round if Overclocked, regardless of cost of the Banana Farm that was Overclocked, as their attack speeds are essentially the rate at which they produce bananas.
  • Cooldown of 45 seconds upon usage.


  • As it costs extremely high just for one support upgrade, it is better off using Ultraboost for late-game. Particularly, use on Sun Temples and True Sun Gods.
  • One permanent boost on a Monkey Village or a Banana Farm grants the effect of a tenth of an Overclock. 10x permanent boost is roughly the same as a normal Overclock on those towers. These effect are also stackable with an Overclock effect. Eg. a farm with maximize boost and an active Overclock will generate 4x income per round than usual.
    • However, it seems that 10x permanent boost will actually grant 1 extra banana/crate drop on a farm from its already-boosted income.
  • As with Overclock, Ultraboosting a Monkeyopolis will not increase income production, but will increase its range.

Version HistoryEdit


Nerf Ultraboost attack speed boost reduced (100% --> 66%)

Nerf Ultraboost permanent attack speed gain reduced (10% --> 6.66%, up to 66% attack speed permanent boost instead of 100%)


Buff Ultraboost will now apply "perma" stacks upon ability activation rather than expiration

Buff Ultraboost's regular Overclock effect's ability buff state will now be included in save files



  • Ultraboost is tied with Flying Fortress for the fourth most expensive upgrade in the game, behind Super Mines, Legend of the Night and True Sun God.
  • Ultraboost is the most expensive upgrade to be purchasable on CHIMPS Mode before Round 100. This feat was first achieved by a user who was attempting this on Logs CHIMPS. The same challenge was attempted by Flying Fortress by other players, but failed due to extra costs.
    • In 18.0, the addition of Admiral Brickell allowed Flying Fortress to be barely afforded in CHIMPS. The 18.1 nerf made it much harder to afford a Flying Fortress, but it remains still possible.
  • Unlike the Overclock ability, a techbot can use its ability on an Ultraboost tower. If so, it will automatically reuse the ability on the previously targetted tower.
    • In Version 16.0, Overclock can be linked to a techbot too, and it will also overclock the previously targeted tower.
  • Similar to Overclock, Version 14.0's official patch notes has an error regarding the Ultraboost attack speed boost nerf. The nerfed attack speed boost was actually from +100% to +66% instead of to +80%, and the permanent boosts are decreased from +10% to +6.66%; this mistake is likely due to a confusion between the concepts of attack cooldown (i.e. for the multiplicative increase/decrease for an attack per unit time) and attack speed (i.e. for the percentage increase/decrease for the numbers of attacks per second). This discrepancy was explained on the official BTD6 subreddit here.
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