Geth Prime

Mass Effect
Standing twelve feet high and boasting the deadliest arsenal of any geth infantry, a Geth Prime is a terrifying opponent. They are instantly recognizable by their white armor and huge stature. Primes carry a pulse rifle and rocket launcher, have five levels of shielding and are incredibly resilient. They also boost nearby geth combat stats; it is this ability that sets them apart from the Geth Juggernaut. Primes have no major weaknesses and are resistant to biotic and tech talents. They are the largest bi-pedal geth unit, towering over the second largest unit, the Geth Juggernaut.

Tactics
The Geth Prime is used as not only a morale booster for other geth in combat, but also as an elite soldier. They are put into action where the geth need extra armor and firepower. Geth Primes have the Combat VI ability which boosts the combat prowess of all nearby geth, resulting in a faster rate of fire, better accuracy and more damage. Consequently it is a good idea to take out Geth Primes first before focusing on smaller geth.

Trivia
Geth Prime units on the Pinnacle Station subterranean survival mode are equipped with a large, bluish-glowing version of the Pulse Rifle, which functions in the same manner as the normal Pulse Rifle.

Mass Effect 2
In Mass Effect 2, Geth Primes are armed with the M-76 Revenant machine gun, which they fire in long bursts, and a siege pulse cannon. They also have the ability to boost stats of nearby geth and can also deploy combat drones.

Fighting the Geth Prime is not unlike fighting an YMIR Mech, both will attempt to engage at point blank range. Disruptor Ammo and Armor Piercing Ammo, if available, are very effective against their shields and armor, respectively.