Keep in mind that Tier 4 requires four Refined Aetherium Crystals and Tier 5 requires five Flawless Aetherium Crystals. Each tier will increase the additional damage the mod does. Much like other things in the game, you’re also able to upgrade Ammo Mods using Aetherium Crystals. 4 GB will also be needed to achieve the Call of Duty: Black Ops 2 rec specs What do you need to upgrade ammo in Black Ops?
Call of Duty: Black Ops 2 requires at least a Radeon HD 4850×2 or GeForce GTS 450 to meet recommended requirements running on high graphics setting, with 1080p resolution. PC System Analysis For Call of Duty: Black Ops 2 Requirements.
What do I need for Call of Duty Black Ops 2?