T3 vs T2 EC2: Save Costs and Avoid CPU Throttling in AWS

If you’re using T2 instances, you might be paying more while dealing with CPU throttling. Here’s why T3 is a better option.

Sanjay Yadav

16 Feb 2026 • 3 min read

Why This Comparison Still Matters

In many AWS accounts we still see T2 instances running production workloads. Most of the time, this isn’t by choice. It’s usually inheritance — old templates, old AMIs, or “this is what we launched years ago”.

The issue here is: you are likely paying more money for worse performance.

How Burstable EC2 Instances Originally Worked

When AWS introduced T2 instances, burstable compute was a solid idea.

You received:

A low baseline CPU
CPU credits earned during idle time
The ability to burst when needed

For small, spiky workloads, this model worked well enough at the time. T2 became the default for running applications on top of ec2 instances.

Where T2 Starts to Fall Apart

Over time, several issues became obvious.
In real environments:

Baseline CPU performance is low
CPU credits accumulate slowly
Unlimited bursting costs extra
Performance becomes unpredictable under sustained load

In most teams, this shows up as mysterious CPU throttling, even though the instance size “should” be enough.

What Changed With T3

T3 instances are not just a pricing refresh.
They are built on AWS Nitro, which fundamentally improves how compute is delivered.
The result is:

Higher baseline CPU
Faster CPU credit earning
More consistent performance
Lower cost for equivalent instance sizes

This is why AWS positions T3 as the replacement for T2.

How CPU Credits Differ Internally

CPU Credit Behavior (High Level)

Diagram comparing CPU credit behavior between AWS T2 and T3 burstable EC2 instances

The key difference is not just bursting — it’s how quickly credits are earned and how predictable performance is once credits are spent.

Practical Cost Reality

For the same workload:

T2 often ends up more expensive
T3 delivers better throughput
Unlimited bursting on T2 adds surprise costs

Once sustained CPU usage enters the picture, T2 stops being economical very quickly.

Practical Example

If you are running:

APIs
Background workers
Small application servers
Internal tooling

T3 will almost always behave better under real traffic patterns.
In practice, many teams switch to T3 and immediately notice fewer CPU-related alerts without changing instance size.

Operational Considerations

There is no special configuration required to use T3.
From an operations perspective:

IAM remains unchanged
Monitoring stays the same
Autoscaling behavior improves due to more stable CPU usage

This makes T3 a low-risk upgrade in most environments.

Migration Guidance

Migrating from T2 to T3 is usually straightforward:

Ensure your AMI supports Nitro-based instances
Launch a T3 instance of the same size
Observe CPU credit behavior and latency
Roll out gradually if the workload is critical

The biggest blocker is often legacy AMIs, not application behavior.

When to Use T3 vs When Not To

Use T3 When:

Launching new workloads
Running general-purpose services
Cost efficiency matters
You want predictable burst behavior

Use T2 Only When:

You are stuck with legacy AMIs
Nitro is not supported
Migration is temporarily impossible

Even then, T2 should be treated as a short-term compromise.

FAQ

1. Is T3 cheaper than T2 in AWS EC2?

In most real-world scenarios, T3 instances are more cost-efficient than T2. They offer improved baseline performance and flexible CPU credit usage, which helps reduce unexpected costs.

2. What are CPU credits in T2 and T3 instances?

CPU credits allow burstable instances to handle temporary spikes in usage. T2 instances have stricter credit limits, while T3 provides more flexible credit options, making it better for variable workloads.

3. When should I choose T3 over T2?

You should choose T3 when your workload requires consistent performance or occasional bursts. T3 is generally better for modern applications due to its cost-performance balance.

Conclusion

T2 instances are effectively legacy at this point.
T3 instances are cheaper, faster, and operationally simpler.

For anything new, T3 should be the default.
T2 should exist only where history forces it to.

That single decision can quietly reduce cost and eliminate an entire class of performance issues.