AWS C3 Vs. C4 Vs. C5 Instances: A Side-By-Side Comparison

The Amazon EC2 C instance family provides high compute power with low latency for compute-intensive use cases. C3, C4, and C5 instances are just three of fourteen instances that make up the Compute-Optimized category of Amazon EC2 instances.

In this guide, we compare the differences between C3, C4, and C5 instances. We’ll also cover a handy tool to help you choose the best option for your requirements between C3, C4, and C5 instances.

What Are Amazon EC2 C3 Instances?

Amazon C3 instances have a higher ratio of compute power to memory, which enables them to handle compute-intensive workloads such as parallel computing and machine learning.

AWS introduced the 64-bit processor instances in 2013 with double the per vCPU memory and instance storage (SSD-based) as C1 instances. C3 instances were at the time the best high-performance instance type on the AWS platform, owing to their superior price-performance balance.

C3 instances also support Enhanced Networking, SSD storage, and higher network performance (up to 10 Gbps using c3.8xlarge) than the C1 type.

You can also launch C3 instances as On-Demand, Reserved, or Spot instances, increasing their flexibility. Here are some more C3 instance features to know:

Instance type and size	32-bit or 64-bit	vCPU	Memory in GiB	Instance storage in GB	EBS-optimized	Network performance
c3.large	32 or 64	2	3.75	2 X 16	N/A	Moderate
c3.xlarge	64	4	7.5	2 X 40	Yes	Moderate
c3.2xlarge	64	8	15	2 X 80	Yes	High
c3.4xlarge	64	16	30	2 X 160	Yes	High
c3.8xlarge	64	32	60	2 X 320	N/A	10 Gbps

What Are Amazon EC2 C4 Instances?

Two years after launching C3 instances, AWS introduced C4 instances, which were EBS-optimized by default and had slightly faster processors. Accordingly, C4 instances can handle a wide variety of top-of-the-line workloads, including high-performance web servers, dedicated ad server engines, and media transcoding.

C4 instances provide more compute units, a higher EBS throughput, and faster networking than C3 instances, even with the same number of vCPUs and memory. That means C4 instances can actually deliver more value for the same price as C3 instances.

You can also alter C4 instances’ busy and idle states (the cores’ P-state and C-state), influencing performance.

Here’s another thing. In previous-generation C3s, local SSDs provide ephemeral storage. On paper, local SSD storage should provide faster speeds than the EBS route because the SSDs are physically attached to the instance — and so do not need network bandwidth to work. The downside is, as soon as C3 instances shut down, they lose all their data since the SSDs do not persist the data.

What Are Amazon EC2 C5 Instances?

As some of the latest-generation instances on AWS, Amazon C5 instances deliver up to 19 Gbps of dedicated EBS bandwidth, between 10 Gbps and 25 Gbps Enhanced Networking, and run on the AWS Nitro System.

There are six types of C5 instances, each of which serves a unique use case. We’ve covered each C5 instance type in more detail in this C5 vs M5 instances comparison. But here’s a quick primer.

And now, for the head-to-head comparison.

AWS C3 Vs. C4 Vs. C5 Instances: Side-By-Side Comparison

	Amazon C3 instances	Amazon C4 instances	Amazon C5 instances
Specialty	Compute-intensive workloads for users who haven’t upgraded to new-generation AWS instances	Compute-bound applications requiring EBS optimization by default and faster processing for the same or better price	Modern, high-performance use cases at great price-performance
Processor	2.8 GHz Intel Xeon E5-2680v2 (Ivy Bridge processor)	2.9 GHz Intel Xeon Scalable Processor E5-2666v3 (Haswell processor)	3.4 GHz (all core Turbo) or 3.5 GHz (single core Turbo) 1st or 2nd generation Intel Xeon Platinum 8000 Series (Skylake 8124M) or second generation Intel Xeon Scalable Processors (Cascade Lake 8275CL) clocked at 3-6 GHz (all core Turbo) or 3.9GHz (single core Turbo)
Max number of cores per instance	16	18	48
Max memory	60GiB	60 GiB	192 GiB
Instances sizes available	c3.large c3.xlarge c3.2xlarge c3.4xlarge c3.8xlarge	c4.large c4.xlarge c4.2xlarge c4.4xlarge c4.8xlarge	c5.large c5.xlarge c5.2xlarge c5.4xlarge c5.9xlarge c5.12xlarge c5.18xlarge c5.24xlarge c5.metal These sizes are also available for c5n, c5a, c5d, and c5ad instances
Network bandwidth	Moderate to high	Up to 10 Gbps	Up to 25 Gbps
EBS bandwidth	EBS-optimized available	Up to 4 Gbps	Up to 19 Gbps
Best use cases	Moderately compute-intensive web servers, batch processing, and analytics	High-performance web servers, video encoding, and distributed analytics	Advanced HPC, ad serving engines, batch processing, etc

Rightsize Your Instances With CloudZero Advisor

We get it. Determining the right Amazon EC2 instance type and size for different applications can be daunting.

Each configuration will certainly affect your app’s performance and cloud costs differently. For example, if you provision one size bigger than necessary, you could end up wasting thousands of dollars every month in unused capacity.

The problem is that configuring instances can often be a trial-and-error process, especially when you are launching a new project and aren’t sure how many resources it will require.

It’s also hard to predict demand over the first few months. Yet you don’t want to have to update your instances too often because each time you do so, you run the risk of more downtime and not meeting your SLAs.

With CloudZero Advisor, you can avoid all that hassle. With this free tool, you can find the best instance based on several factors, like AWS Region, service, pricing, and resource type, as well as instance type and size. Use CloudZero Advisor for free here.