AWS EC2 C8in and C8

7 min. read

As of: 22.04.2026

On 20 April 2026, AWS made the EC2 instances C8in and C8ib generally available. C8in delivers up to 600 Gbps of network bandwidth and scales to 384 vCPUs; C8ib offers up to 300 Gbps of EBS bandwidth. Both run on custom 6th-gen Intel Xeon Scalable processors and 6th-gen Nitro cards. For in-memory databases, streaming analytics, and HPC clusters, this shifts the upper bound of what AWS can deliver.

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What C8in and C8ib Actually Change

C8in and C8ib are the network- and storage-optimized variants of the C8 family. The base generation, C8i and C8i-flex, has been available since October 2025 and delivers up to 15 percent higher performance than C7i, according to AWS. C8in stacks 600 Gbps network on top of that; C8ib adds 300 Gbps EBS. The logic behind the naming convention has been consistent for years: “n” stands for Network, “b” for Block Storage. Anyone who has built with C6in or C7in knows the pattern — what’s new is the delta.

That delta comes from two directions. First: the sixth generation of the custom Intel Xeon Scalable, which AWS deploys exclusively in its own fleet. DDR5-7200 DIMMs, higher memory bandwidth, improved turbo behavior under single-thread load. Second: the new Nitro generation, which is what actually enables the 600 Gbps network upgrade in the first place. Nitro 6 brings the PCIe Gen 5 path to the NIC and pushes DMA overhead further out of the CPU. For teams who have already worked through iperf3 benchmarks on C7i and M7i, this is exactly where the old limits break.

For purchasing decisions, that means: anyone who previously chose X2iedn for in-memory databases or C7gn for network throughput now has a second option in the x86 path with C8in. The Graviton line remains the more cost-effective choice for ARM-compatible workloads. C8in targets the fraction that must stay on x86 for licensing or binary compatibility reasons.

Where 600 Gbps Actually Matter

Theoretical bandwidth only matters where a workload can actually saturate the network. In practice, three patterns emerge. First: in-memory databases and cache layers such as Valkey, KeyDB, or Dragonfly, which saturate the network path between nodes during multi-master replication. Anyone who has optimized for 100 Gbps and seen CPU sitting idle because the NIC was the bottleneck will find a generational leap with C8in. Second: streaming analytics setups where Kafka brokers, Flink workers, and object-store sinks run together in the same VPC. For topics with double-digit GB/s sustained throughput, architectures have historically relied on multi-NIC setups — 600 Gbps single-NIC removes a layer of that complexity.

Third: HPC and AI training clusters that don’t use Inferentia or Trainium, but instead rely on classic x86-with-GPU or CPU-only configurations. Here, EFA matters. AWS has restricted EFA on C8in to the large sizes — 48xlarge, 96xlarge, metal-48xl, metal-96xl. Anyone who needs an Elastic Fabric Adapter in their cluster cannot start with smaller sizes and scale up later without switching instance families. This forces an early architectural decision.

The fourth workload class most often mentioned by reflex is video processing. In practice, C8in delivers less here than expected: most transcoding pipelines are either GPU-bound or run on accelerated instances such as VT1. 600 Gbps helps where H.265 ingest runs in real time from multiple simultaneous sources — a narrow segment.

When C8ib Is the Right Choice

C8ib is the less talked-about of the two instances, but the more straightforward choice. Workloads with high EBS throughput — transactional databases with large write-ahead logs, data warehouses with massive commit rates, classic SAP HANA single-node instances with backup streams — have been storage-limited for years, not compute-limited. Anyone running an r6idn or i4i today and seeing CPU underutilization while EBS queue depth remains consistently high will find a direct path to better EBS saturation with C8ib.

The distinction from local instance storage is important. C8ib uses EBS, not NVMe local disks. Anyone needing NVMe scratch space — for Spark shuffle or HDFS-like pipelines, for example — stays with the “d” variants (C8id, M8id, R8id), available in select regions since late 2025. AWS’s product positioning is clear: EBS-heavy means C8ib, local NVMe means C8id.

Network and storage are two bottlenecks, not one. Anyone who needs both simultaneously either builds two clusters — or waits for the instance that bundles both. For now, the separation between C8in and C8ib is cleaner than any halfway solution.

Benchmark perspective: when the switch pays off

The practical question for architects and infrastructure leads isn’t “is this faster” — it’s “how much of that speed actually reaches my workload.” With in-memory databases, packets per second matter just as much as nominal bandwidth. Nitro 6 improves both simultaneously, but the delta is workload-dependent. If you’re running C6in today with a Valkey or Redis cluster and your cross-node replication sits below 50 percent of NIC capacity, C8in delivers a moderate gain. If you’re consistently pinned at the 80-percent mark, tripling the network bandwidth buys back real headroom for growth.

For Kafka and Flink clusters the logic is similar, with one additional variable: broker-to-broker replication. At replication factor 3 with acks=all, write throughput scales with broker NIC bandwidth — not CPU. Here, 600 Gbps per node is a genuine relief if your topic structures previously had to spread across four or five brokers just to get the network throughput. With C8in, the same workloads run on fewer brokers, which means lower operational complexity.

For database-heavy workloads, the picture is different. With PostgreSQL or MySQL using synchronous replication, the network is rarely the bottleneck — fsync latency and EBS IOPS rate are what count. That makes C8ib, not C8in, the right call, even though both instance types were announced in the same breath. Running both in parallel — say, a PostgreSQL cluster on C8ib and a Kafka fanout on C8in within the same VPC — delivers a double benefit without forcing a compromise instance. That’s the real signal behind these two variants: AWS is deliberately separating network headroom and storage headroom rather than bundling them into a pricier combo instance that most teams simply don’t need.

What Teams Should Check Now

Reservation and capacity availability will be the real test over the coming weeks. AWS has launched C8in and C8ib in select regions initially, according to the launch announcement; Frankfurt, Ireland, and Virginia are typically among the first in early waves. Teams looking to port workloads should review the Availability Zone matrix in the Management Console and hold off on Savings Plans commitments until the instance family is available in their three to five target regions.

For existing migrations, the cost ratio relative to the current family is what matters. AWS has not yet confirmed DACH-specific on-demand list prices for all regions at launch — the premium over C7i on C8i was roughly seven to ten percent, depending on region. A similar markup over C7in and C7i is realistic for C8in and C8ib. Teams running FinOps models on a per-Gbps basis should measure that delta against real utilization before locking in any Savings Plan commitment.

The third check concerns the stack above. AMI compatibility with 6th-gen Xeon features is generally non-critical, but kernel versions below 5.15 have shown driver issues with Nitro 6 NICs in isolated cases. Teams running Ubuntu 22.04 LTS or Amazon Linux 2023 get the drivers out of the box; those on RHEL 8 or older should schedule migration testing early. For SAP HANA and Oracle environments, the certification list also warrants a look: single-node HANA on C8i and C8ib is expected to be certified, while C8in is overkill for pure HANA workloads and remains more relevant for analytics sidecars like Spark or Trino.

The fourth check is observability. Monitoring 600 Gbps concurrently is not a CloudWatch default task — Enhanced Monitoring at one-second intervals carries additional cost and produces data that quickly gets lost in the noise without properly configured alert thresholds. Teams making the jump typically deploy Prometheus or OpenTelemetry at the node level and export NIC statistics per interface. The 200 Gbps era made it clear: without a clean baseline measurement, nobody notices whether a new instance is actually using its capacity or just idling at a higher price.

Fifth, the FinOps angle: C8in and C8ib are cheaper per Gbps, not per vCPU. Deploying these instance families without a workload profile check means paying the network premium even when the application only pulls four Gbps. The pattern is familiar from the M6in and R6in rollouts — in the months following general availability, teams reflexively migrate to the new family and only realize in the next quarterly review that an M7i or C7i would have handled the same workload for less. The right sequence remains: measure the profile, identify the bottleneck, then switch instance families.

Frequently Asked Questions

What is the difference between C8in and C8ib?

C8in is network-optimized with up to 600 Gbps of network bandwidth, while C8ib is storage-optimized with up to 300 Gbps of EBS bandwidth. Both run on the same 6th-gen Intel Xeon Scalable and Nitro-6, but differ in their I/O characteristics.

Which workloads benefit most from C8in?

In-memory databases with multi-master replication, streaming analytics with Kafka/Flink/object store within a single VPC, and HPC clusters with EFA. The rule of thumb: if the NIC is the bottleneck rather than the CPU, C8in makes a real difference.

Is Elastic Fabric Adapter available on C8in?

Yes, but only on the 48xlarge, 96xlarge, metal-48xl, and metal-96xl sizes. Smaller sizes do not support EFA — for HPC and AI training clusters, this means committing to your architecture early.

Are C8in and C8ib available as Graviton variants?

No. C8in and C8ib are based on custom 6th-gen Intel Xeon Scalable processors. For ARM-compatible workloads, the Graviton generation (C7gn, C8g once available) remains the more cost-efficient option.

In which regions are C8in and C8ib available?

AWS typically launches GA releases of this family in major regions such as US-East-1, US-West-2, Ireland, and Frankfurt. Check the current availability matrix in the EC2 console before committing to reservations or Savings Plans.

Image source: Pexels / Brett Sayles (px:5050305)