New T8i instances, time to retire your T3i?
T8i offers immediate gains of up to 70% in processing performance with a price-performance savings of up to 30%. Migrate from T3 It's a no brainer decision?
This is the english version of the original post in spanish
Introduction: What does the T8i family offer?
Amazon EC2 T8i instances are the latest version of low-cost burstable instances on AWS. They are powered by the AWS Nitro System and custom 6th generation Intel Xeon Scalable (Granite Rapids) processors. They are designed for low- to moderate-CPU workloads (such as microservices, development/testing environments, low-traffic websites, and batch processing).
And what's the difference with my venerable T3s?
Legacy Processor Architecture: T3 instances were released in 2018; in computing, an 8-year difference is like... years of a dog
Your t3.medium is older than you think.
Lower Compute Performance: The new T8i instances offer up to 70% more compute performance, 1.25 times more network bandwidth, and 2.4 times more bandwidth for EBS compared to T3.
Great, the T8i are faster, should I upgrade now?
Not quite fast, due to improvements in both CPU and memory AWS claims to offer up to 30% better price-performance ratio compared to T3. However, in the press release they don't mention that are 20% more expensive.
Also, keep in mind that the T8i is not yet covered by the savings plans and may not be available in your region.
Cost- and performance-based alternatives to T3
When evaluating a migration strategy from T3, there are different scenarios depending on the usage pattern and the required size:
- Direct replacement for T8i: T8i only offers the sizes
nano,micro,smallandmediumDirect replacement has no risk from a performance prespective since the amount of CPU and memory is the same. - Dedicated performance instances without credits (
c6a,m6a,c7i-flex): Scenario for applications with continuous or sustained CPU usage where T-series credit limits create cost overruns or bottlenecks. - Memory-optimized instances (
r6a,r8i-flex): Recommended for workloads that exceed the size of T8i or that require maintaining the memory size. - Migration to AWS managed solutions: It is an uncommon use case, but in certain situations migrating the EC2 machine to the AWS managed solution can save costs.
3. Migration Scenarios and Comparisons
Scenario 1: T3 vs T8i for sizes smaller than large (nano, micro, small, medium)
For smaller sizes, migrating to T8i provides up to a 70% increase in computing performance and greater network/EBS capacity, achieving an overall price-performance improvement of up to 30%.
If the CPU is the bottleneck in the current T3, migrating to T8i can eliminate the bottleneck.
Furthermore, if the T3 instance is consuming credits in unlimited mode, the CPU upgrade will also cause lower credit consumption, which can offset the 20% cost increase.
| Metric / Characteristic | T3 Family (< large) | T8i Family (< large) |
|---|---|---|
| Processor | Intel Xeon Platinum (up to 3.1 GHz) | Intel Xeon Scalable n (up to 3.8 GHz) |
| CPU Performance | Previous Baseline | Up to +70% Compute Performance |
| Network Bandwidth | Up to 5 Gbps (t3.medium) | Up to 6.25 Gbps (t8i.medium, 1.25x greater) |
| EBS Bandwidth | Up to 2,085 - 2,780 Mbps | Up to 2.4x greater EBS bandwidth |
| Example of On-Demand Costing | t3.medium: $0.046 / hour | t8i.medium: $0.055 / hour |
Scenario 2: t3 vs m6a, c6a and c7i-flex for applications with high CPU usage and low memory.
In applications with low but constant CPU usage, T3 instances can become a cost trap due to their CPU credit-based architecture:
- The risk of credits in T3: In Standard mode, if accumulated credits are depleted, CPU performance is drastically restricted to the baseline (e.g., 30% per vCPU in
t3.largeIn Unlimited mode (enabled by default), if the 24-hour average usage exceeds the baseline, AWS charges an additional $0.05 per vCPU-hour. If an instancet3.large(2 vCPUs) runs at 100% CPU continuously, the surcharge adds $0.10/hour, raising the total actual cost from ~$0.0835/hour to ~$0.1835/hour. - The advantage of
m6a,c6aandc7i-flex: These families offer dedicated vCPUs with 100% constant performance, eliminating credit volatility and guaranteeing fixed capacity.
Migrate to families of the type
c It allows you to change the CPU and memory ratio (2 GB of RAM per vCPU). This option is only valid if less than 50% of the memory is being used in the current t3 instance.If, on the other hand, you want to maintain the CPU and memory ratio, you should opt for a
m6aThis option is only valid if the t3 instance is consuming credits in unlimited mode, causing additional costs.| Instance | vCPUs | Memory (GiB) | CPU Architecture | On-Demand Price (per hour) |
|---|---|---|---|---|
t3.large | 2 | 8 | Intel Xeon 1st/2nd Gen (30% baseline / requires credits) | $0.091 (+$0.10/h if credits are consumed) |
c6a.large | 2 | 4 | 100% Dedicated (AMD EPYC) | $0.082 |
m6a.large | 2 | 8 | 100% Dedicated (AMD EPYC 7R13 @ 3.6 GHz) | $0.096 |
c7i-flex.large | 2 | 4 | 100% Dedicated (Sapphire Rapids @ 3.2 GHz) | $0.091 |
Scenario 3: t3.xlarge vs r8i-flex.large for applications with low CPU usage and high memory requirements.
Since the T8i does not offer a size
largeAWS recommends migrating larger sizes to Flex instances.If the application is not CPU-intensive and you want to maintain the same amount of memory, you can replace the t3.xlarge instances with r8i-flex.large. The R8i family processor is 70% more powerful than the T3 family CPUs; even if you halve the number of vCPUs, the 70% performance improvement might compensate for the difference.
After making this change, it is necessary to monitor the computer's CPU to confirm that the performance is acceptable.
| Instance | vCPUs | Memory (GiB) | CPU Architecture | On-Demand Price (per hour) |
|---|---|---|---|---|
t3.large | 4 | 16 | Intel Xeon 1st/2nd Gen (30% Baseline) | $0.182 |
r8i-flex.large | 2 | 16 | Intel Xeon Scalable Granite Rapids @ 3.9 GHz | $0.148 |
Scenario 4: Migration to AWS managed solutions
I recognize that it is an atypical case, but I have had clients in this situation.
Sometimes we tend to use EC2 instances instead of AWS managed solutions, trying to save money on our monthly bill. But these solutions can become obsolete due to AWS pricing changes.
Real case in one of my clients.
Machine t3.micro used as a Redis server $0.011 per hour. The server had an associated public IP address which added $0.005 to the hourly cost.
The server was set up years ago, and many things have happened since then:
- Amazon offers 2021 Redis servers with T4G
- 2024 AWS starts charging for public IPs
- 2025 AWS launches Valkey at a price below the cost of Redis.
The T3 you set up thinking you were saving money turns out to be more expensive than its managed equivalent.
| Instance | On-Demand Cost | IP Cost | Total |
|---|---|---|---|
| t3.micro (EC2) | $0.0110 / hour | $0.005 / hour | $0.0160 / hour |
| t4g.micro (Valkey) | $0.0136 / hour | $0.0136 / hour |
(*) The cost of the EBS disk has been omitted from the totals.
Migrating an x86 machine to Arm64 can typically be quite involved, but by delegating to a managed AWS service, the system optimization for Arm64 is handled. This use case only makes sense for small machines where the cost of a public IP address might have a greater impact.
Conclusion
The T3 family is not outdated; it remains a cost-effective option for environments with low CPU usage. For environments with sizes equal to or smaller than
mediumAdopting T8i offers immediate gains of up to 70% in processing performance with a price-performance savings of up to 30%. For instances large or higher, natural migration should be directed towards Flex instances (7i or 8i families) or towards dedicated AMD alternatives (c6a / m6a) to definitively eliminate the overhead caused by CPU credit management.Enjoyed reading this content? Let the author know!
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