Call of Duty: Modern Warfare 2's controversial perk system works differently from the traditional tried and tested system of the past. You can run four perks now, but these benefits are split between base, bonus, and ultimate tiers. The biggest change is that the higher-tiered perks only activate after a certain amount of time passes, four for bonus perks and eight minutes for ultimate perks.

RELATED: Call of Duty: Modern Warfare 2 - The Fastest Way Of Leveling Up

If you're a flanker running a stealth loadout, don't expect to wrap around the enemy until you earn all your perks. But kills, assists, and objective time help get all your perks online faster. Racking up points fast is crucial because these great perks offer a significant advantage over your opponents.

10 Overkill

Modern Warfare 2 perk menu describing the overkill perk

Overkill is a perk for versatile players because it lets you carry two primary weapons in one loadout. A common combination is equipping two weapons that excel at different ranges. For example, pairing a strong marksman rifle with a shotgun lets you take firefights from two extreme ranges, up close and far away.

A cheesy and slightly goofy use of the Overkill perk is pairing your favorite weapon with the Riot Shield. When you have the Riot Shield equipped in your loadout, it will remain on your back when not in use. So, you can rush around on your SMG without worrying about enemies behind you.

9 Scavenger

Modern Warfare 2 perk menu describing the scavenger perk

The Scavenger perk lets you resupply ammo and Throwing Knives from operators' bodies. Scavenger is a must-have perk to use if you're deep behind enemy lines. But other perks give more value if you're dropping without expending your whole ammo reserves.

RELATED: Call Of Duty: Modern Warfare 2 - Best Field Upgrades

Using the Scavenger perk in your build lets you take other field upgrades than the Munitions Box. Rather than wasting a slot for the ammo box, you could bring the Dead Silence, Portable Radar, or DDOS to clear your flank routes.

8 Battle Hardened

Modern Warfare 2 perk menu describing the battle hardened perk

Most Call of Duty players are pretty loose with their lethal and tactical equipment. Every lobby is filled with a rain of grenades haphazardly exploding, and sometimes players can get lucky and actually hit their mark. Fortunately, the Battle Hardened perk reduces the intensity of enemy flash, stun, gas, shock and EMP effects.

Additionally, the perk also grants immunity to Snaphot grenades. This valuable perk nullifies the opposing team's disruptive capabilities, letting you hold the angle uncontested. While the effects will still apply, Battle Hardened allows you to fight back.

7 Hardline

Modern Warfare 2 perk menu describing the hardline perk

Due to the timed perk system, players won't have Ghost online until late into the match. This new system makes the UAV one of the best Killstreaks since your team will get the max value out of it. Hardline reduces killstreak cost by one elimination or lowers the Scorestreak cost by 125.

Killstreaks are game-changing in Modern Warfare 2, allowing you to snowball your lead into a team-wide advantage. After all, no one will challenge your objective with a VTOL jet guarding the location.

6 Double Time

Modern Warfare 2 perk menu describing the double time perk

Fluid movement and smart rotations are important fundamentals for any Call of Duty players looking to improve their gameplay. The Double Time perk doubles the duration of Tactical Sprint, letting you play the map at lightning speeds. Additionally, the perk also increases crouch movement speed by 30%, a niche but welcome benefit.

You can get more value from Double Time on a larger map like Zarqwa Hydroelectric. In a game with advanced weaponry and the latest military technology, a strong pair of legs is one of the best pieces of equipment a soldier can have.

5 Cold-Blooded

Modern Warfare 2 perk menu describing the cold blooded perk

The Cold-Blooded perk will save you from many deaths you never knew were coming. This life-saving perk practically makes you invisible since it makes you undetectable by AI targeting systems and thermal optics. So that means dangerous Killstreaks like a Chopper Gunner or a Sentry Gun won't see you. Just avoid standing next to your teammates, or you'll get caught as collateral.

RELATED: Call of Duty: Modern Warfare 2 - Tips For Beating The Campaign On Veteran Difficulty

Additionally, you're immune to enemy Tactical Cameras, Recon Drones, and Spotter Scopes. While they can see you, they can't highlight you for their team. If that's enough, you also won't trigger the High Alert warning, letting you sneak up on complacent players.

4 Bird's Eye

Modern Warfare 2 perk menu describing the birds eye perk

Bird's Eye is a massively underrated perk because it isn't as flashy as the rest of the ultimate perks. The Bird's Eye perk zooms out the minimap, giving you a better view of the battlefield. Its strongest feature is that UAV and Radar pings reveal the enemy's direction, which means you'll know exactly what angle they're holding.

Getting Bird's Eye during the match pings all the enemies on the minimap. Bird's Eye is an obvious choice for any sniper, but it's also potent on flankers since you'll know how to avoid the enemy's sight lines.

3 Ghost

Modern Warfare 2 perk menu describing the ghost perk

Ghost is a classic Call of Duty perk which renders you undetectable by UAVs, Portable Radars, and Heartbeat Sensors. As soon as this ultimate perk comes online, you can roam the map without fear of enemies pre-aiming your location. However, enemies can still hear your loud footsteps if you're sprinting.

Pair Ghost with Cold-Blooded and a suppressor, and you're practically invisible to the enemy team. This perk is a must-have to round out any stealth loadout.

2 Fast Hands

Modern Warfare 2 perk menu describing the fast hands perk

Fast Hands is a bonus perk that lets you reload, use equipment, and swap weapons much faster. This perk has no downsides because it makes you a much more efficient fighter. Whether you need a bit more reload speed for your shotgun or need to compensate for the slow reload animation of a sniper, Fast Hands is always good to have to empower the best weapons.

Fast Hands is also an important perk if you're running a Riot Shield with a weapon or a throwing knife. The faster transition between holding your shield and pulling out your weapon is crucial to its gameplay.

1 Quick Fix

Modern Warfare 2 perk menu describing the quick fix perk

Infinity Ward has drastically lowered the time to kill in Modern Warfare 2. Every gunfight feels like you barely made it out, and you often have to sit down and regenerate after each duel. Quick Fix is a fantastic perk because it immediately triggers health regeneration after eliminating a player.

Quick Fix also boosts health regeneration rate when capturing or holding objectives. Whether you have a hyper-aggressive loadout or a rare player who holds the objective, you'll encounter intense gunfights much more than a passive camper. Quick Fix will massively increase your survivability in this fast-paced game.

NEXT: Changes To Make Call Of Duty Modern Warfare 2 Go From Good To Great