In StarCraft, each protoss player has two psi counters - the first refers to the amount of psi being consumed by the player's units and the second refers to the amount of total psi available. The difference in the two numbers is the amount of psi that is still available for constructing additional units. Once the difference in the two numbers reaches zero, a player will not be able to construct any additional units. Hidden is a 200 point psi max, the limit beyond which your production structures can no longer turn out units no matter how many psi production objects you create.

Psi is the protoss equivalent of supply or control.

StarCraftEdit

The dark archon mind control ability can result in the amount of used psi, or control or supply, exceeding the 200 point limit. While legal, this means no further units can be constructed until the used total falls back below 200. However, another technique that uses mind control allows you to go up to 200 for protoss psi, zerg control, and terran supply each, for a maximum total of 600, by using mind control on workers such as drones and SCVs, and building terran and/or zerg bases. This other technique allows you to build any buildable units or buildings in the game, regardless of race, with up to 600 maximum psi+control+supply.

Generation Table

	Building/Unit
9	Nexus
8	Pylon

Consumption Table

	Building/Unit
1	Probe · Observer
2	Zealot · Dragoon · High templar · Dark templar · Shuttle · Corsair
3	Scout
4	Reaver · Archon · Dark archon · Arbiter
6	Carrier

StarCraft IIEdit

Generation Table

	Building/Unit
10	Nexus
8	Pylon

Consumption Table

	Building/Unit
1	Probe · Observer
2	Zealot · Stalker · High templar · Dark templar · Warp prism · Sentry · Phoenix
3	Void ray
4	Immortal · Archon
6	Carrier · Colossus
8	Mothership