AWS Compute Blog

Optimize costs by up to 70% with new Amazon T3 Dedicated Hosts

This post is written by Andy Ward, Senior Specialist Solutions Architect, and Yogi Barot, Senior Specialist Solutions Architect.

Customers have been taking advantage of Amazon Elastic Compute Cloud (Amazon EC2) Dedicated Hosts to enable them to use their eligible software licenses from vendors such as Microsoft and Oracle since the feature launched in 2015. Amazon EC2 Dedicated Hosts have gained new features over the years. For example, Customers can launch different-sized instances within the same instance family and use AWS License Manager to track and manage software licenses. Host Resource Groups have enabled customers to take advantage of automated host management. Further, the ability to use license included Windows Server on Dedicated Hosts has opened up new possibilities for cost-optimization.

The ability to bring your own license (BYOL) to Amazon EC2 Dedicated Hosts has been an invaluable cost-optimization tool for customers. Since the introduction of Dedicated Hosts on Amazon EC2, customers have requested additional flexibility to further optimize their ability to save on licensing costs on AWS. We listened to that feedback, and are now launching a new type of Amazon EC2 Dedicated Host to enable additional cost savings.

In this blog post, we discuss how our customers can benefit from the newest member of our Amazon EC2 Dedicated Hosts family – the T3 Dedicated Host. The T3 Dedicated Host is the first Amazon EC2 Dedicated Host to support general-purpose burstable T3 instances, providing the most cost-efficient way of using eligible BYOL software on dedicated hardware.

Introducing T3 Dedicated Hosts

When we talk to our customers about BYOL, we often hear the following:

  • We currently run our workloads on-premises and want to move our workloads to AWS with BYOL.
  • We currently benefit from oversubscribing CPU on our on-premises hosts, and want to retain our oversubscription benefits when bringing our eligible BYOL software to AWS.
  • How can we further cost-optimize our AWS environment, increasing the flexibility and cost effectiveness of our licenses?
  • Some of our virtual servers use minimal resources. How can we use smaller instance sizes with BYOL?

T3 Dedicated Hosts differ from our other EC2 Dedicated Hosts. Where our traditional EC2 Dedicated Hosts provide fixed CPU resources, T3 Dedicated Hosts support burstable instances capable of sharing CPU resources, providing a baseline CPU performance and the ability to burst when needed. Sharing CPU resources, also known as oversubscription, is what enables a single T3 Dedicated Host to support up to 4x more instances than comparable general-purpose Dedicated Hosts. This increase in the number of instances supported can enable customers to save on licensing and infrastructure costs by as much as 70%.

Advantages of T3 Dedicated Hosts

 T3 Dedicated Hosts drive a lower total cost of ownership (TCO) by delivering a higher instance density than any other EC2 Dedicated Host. Burstable T3 instances allow customers to consolidate a higher number of instances with low-to-moderate average CPU utilization on fewer hosts than ever before.

T3 Dedicated Hosts also offer smaller instance sizes, in a greater number of vCPU and memory combinations, than other EC2 Dedicated Hosts. Smaller instance sizes can contribute to lower TCO and help deliver consolidation ratios equivalent to or greater than on-premises hosts.

AWS hypervisor management features provide consistent performance for customer workloads. Customers can choose between a wide selection of instance configurations with different vCPU and memory sizes, mixing and matching instances sizes from t3.nano up to t3.2xlarge

You can use your existing eligible per-socket, per-core, or per-VM software licenses, including licenses for Windows Server, SQL Server, SUSE Linux Enterprise Server and Red Hat Enterprise Linux. As licensing terms often change over time, we recommend checking eligibility for BYOL with your license vendor.

You can track your license usage using your license configuration in AWS License Manager. For more information, see the Track your license using AWS License Manager blog post and the Manage Software Licenses with AWS License Manager video on YouTube.

When to use T3 Dedicated Hosts

T3 Dedicated Hosts are best suited for running instances such as small and medium databases and application servers, virtual desktops, and development and test environments. In common with on-premises hypervisor hosts that allow CPU oversubscription, T3 Dedicated Hosts are less suitable for workloads that experience correlated CPU burst patterns.

T3 Dedicated Hosts support all instance sizes of the T3 family, with a wide variety of CPU and RAM ratios. Additionally, as T3 Dedicated Hosts are powered by the AWS Nitro System, they support multiple instance sizes on a single host. Customers can run up to 192 instances on a single T3 Dedicated Host, each capable of supporting multiple processes. The maximum instance limits are shown in the following table:

Instance Family Sockets Physical Cores nano micro small medium large xlarge 2xlarge
t3 2 48 192 192 192 192 96 48 24

Multiple combinations of T3 instance types can be run, up to the memory limit of the host (768GB). Examples of supported blended instance type combinations are:

168 t3.small and 24 t3.large
144 t3.small and 48 t3.large
24 t3.xlarge and 12 t3.2xlarge

Use Cases

If you are looking for ways to decrease your license costs and host footprint in order to achieve the lowest TCO, then using T3 Dedicated Hosts enables a set of previously unavailable scenarios to help you achieve this goal. The ability to run a greater number of instances per host compared to existing Dedicated Hosts leads directly to lower licensing and infrastructure costs on AWS, for suitable BYOL workloads.

The following three scenarios are typical examples of benefits that can be realized by customers using T3 Dedicated Hosts.

Retaining Existing Server Consolidation Ratios While Migrating to AWS

On-premises, you are taking advantage of the fact that you can easily oversubscribe your physical CPUs on VMware hosts and achieve high-levels of consolidation. As you can license Windows Server on a per-physical-core basis, you only need to license the physical cores of the VMware hosts, and not the vCPUs of the Windows Server virtual machines.

  • You are currently running 7 x 48 core VMware Hosts on-premises.
  • Each host is running 150 x 2 vCPU low average-CPU-utilization Windows Server virtual machines.
  • You have Windows Server Datacenter licenses that are eligible for BYOL to AWS.

In this scenario, T3 Dedicated Hosts enable you to achieve similar, or better, levels of consolidation. Additionally, the number of Windows Server Datacenter licenses required in order to bring your workloads to AWS is reduced from 336 cores to 288 cores – a saving of 14%.

On-Premises VMware Hosts T3 Dedicated Hosts Savings
Physical Servers (48 Cores) 7 6
2 vCPU VMs per Host 150 192
Total number of VMs 1000 1000
Total Windows Server Datacenter Licenses (Per Core) 336 288 14%

Reducing License Requirements While Migrating To AWS

On-premises you are taking advantage of the fact that you can easily oversubscribe your physical CPUs on VMware hosts and achieve high-levels of consolidation. You can now achieve far greater levels of consolidation by moving your virtual machines to T3 Dedicated Hosts, which have double the amount of RAM compared to your current on-premises VMware hosts.

  • You are currently using 10 x 36 core, 384GB RAM VMware Hosts on-premises.
  • Each host is running 96 x 2 vCPU, 4GB RAM low average-CPU-utilization Windows Server virtual machines.

By taking advantage of oversubscription and the increased RAM on T3 Dedicated Hosts, you can now achieve far greater levels of consolidation. Additionally, you are able to reduce the number of Windows Server Datacenter licenses required for BYOL. In this scenario, you can achieve a license reduction from 360 cores to 240 cores – a 33% saving.

On-Premises VMware Hosts T3 Dedicated Hosts Savings
Physical Servers 10 5
Physical Cores per Host 36 48
RAM per Host (GB) 384 768
2 vCPU, 4GB RAM VMs per Host 96 192
Total number of VMs 960 960
Total Windows Server Datacenter Licenses (Per Core) = Number of Servers * Physical Core Count 10 * 36 = 360 5 * 48 = 240 33%

Reducing License and Infrastructure Cost by Migrating from C5 Dedicated Hosts to T3 Dedicated Hosts

In this scenario, you are taking advantage of the fact that you can bring your own eligible Windows Server and SQL Server licenses to AWS for use on Dedicated Hosts. However, as your instances all have low average-CPU-utilization, your current C5 Dedicated Hosts, with fixed CPU resources, are largely underutilized.

  • You are currently using C5 EC2 Dedicated Hosts on AWS with eligible Windows Server Datacenter licenses and SQL Server 2017 Enterprise Edition (BYOL).
  • Each host is running 36 x 2 vCPU low average-CPU-utilization Windows Server virtual machines.

By migrating to T3 Dedicated Hosts, you can achieve a substantial reduction in licensing costs. As the total number of physical cores requiring licensing is reduced, you can benefit from a corresponding reduction in the number of SQL Server Enterprise Edition licenses required – a saving of 71%.

C5 Dedicated Hosts T3 Dedicated Hosts Savings
Total Number of Hosts Required 28 6
2 vCPU, 4GB VMs per Host 36 192
Total number of VMs 1008 1008
Total SQL Server EE Licenses = Number of Servers * Physical Core Count 36 * 28 = 1008 48 * 6 = 288 71%


In this blog post, we described the new T3 Dedicated Hosts and how they help customers benefit from running more instances per host in BYOL scenarios. We showed that heavily oversubscribed on-premises environments can be migrated to T3 Dedicated Hosts on AWS while lowering existing licensing and infrastructure costs. We further showed how significant licensing and infrastructure savings can be realized by moving existing workloads from EC2 Dedicated Hosts with fixed CPU resources to new T3 Dedicated Hosts.

Visit the Dedicated Hosts, AWS License Manager and host resource group pages to get started with saving costs on licensing and infrastructure.

AWS can help you assess how your company can get the most out of cloud. Join the millions of AWS customers that trust us to migrate and modernize their most important applications in the cloud. To learn more on modernizing Windows Server or SQL Server, visit Windows on AWS. Contact us to start your migration journey today.