Amazon Web Services : M5 vs M5a vs M6g

AWS M5 / M5a / M6g Benchmark

In other words Intel vs AMD vs ARM. AWS recently released Graviton series for all their main instance types: R6g with extended memory, C6g for compute optimized and M6g for general purpose. Their offering has always been based on Intel but in the past years we saw AMD and now with Graviton 2 making AWS is based on their own chips.

Amazon Web services announces their Graviton processors as a new choice for their customers for increase their performance for a lower cost. But what’s the difference between all these solutions identical on the paper ? Let’s do CPU benchmark to answer it.


For our benchmark, we took 8CPU-32GB VM from each series:

Product Price CPU Frequency
m5.2xlarge 0.38 Intel(R) Xeon(R) Platinum 8175M
Intel(R) Xeon(R) Platinum 8259CL
m5a.2xlarge 0.34 AMD EPYC 7571 2.4-3.0GHz
m6g.2xlarge 0.31 aarch64 N/A

These data are collected by our Cloud Transparency Platform, prices are for us-east (N. Virginia) region.

Performance testing

Prime number search with sysbench CPU

Sysbench CPU can be categorized as arithmetic operations on integer.

We can observe an increase of +100% on single thread and close to 400% between M5 and M6g with 8 threads.

Encryption with AES-256 CBC

Where AMD’s performance depends of block size, Intel and Graviton are homogeneous across sizes. The ARM chip is able to encrypt at 1.2 GB/sec where the M5 and M5a respectively cap at 400MB/sec (200%)  and 900MB/sec (130%).


Product Hourly Monthly
m5.2xlarge 0.38 280 3,360
m5a.2xlarge 0.34 251 3,012 -11%
m6g.2xlarge 0.31 224 2,688 -22%

Monthly is based on 730 hours, yearly on 8,760 hours without long term subscription

Prices make no doubt, each new generation offers a lower cost and M6g owns the lowest.


Depending of your workload, Graviton offers until +400% of performance compared to the Intel analogous. Combined with a lower pricing, M6G is definitively the best EC2 choice for any CPU related workload compatible with ARM architecture.

Check out data in our Public Cloud Reference

New C5a benchmark: Performance/Price

AWS recently released the new series C5a equipped with custom AMD EPYC 7R32. We can discover here, a less expensive alternative to C5, similar to what they did with M5, R5 and T3. But cost isn’t an appropriated metric if you doesn’t take in account performance, so let’s dive into a performance/price benchmark comparing C5 and C5a.

A lower pricing

Name CPU RAM C5 C5a
large 2 4 0.085 0.077
xlarge 4 8 0.170 0.154
2xlarge 8 16 0.340 0.308
4xlarge 16 32 0.680 0.616
9xlarge 36 72 1.530 1.232
12xlarge 48 96 2.040 1.848
18xlarge 72 144 3.060 2.464
24xlarge 96 192 4.080 3.696
metal 96 192 4.080

Pricing is for East US (Ohio)

Performance a bit better

Before open the hood, there are 2 things to keep in mind about C5: CPU performance is highly variable. Behind the product names, several CPU model are sold and we actually collected the following:

  • Intel(R) Xeon(R) Platinum 8124M
  • Intel(R) Xeon(R) Platinum 8275CL

Like the new AMD EPYC 7R32, both are custom models only available at AWS. Next thing, a same CPU model works at different frequencies. Generally, Cloud Providers set their CPU frequency at baseline or turbo frequency, for Platinum 8124M, we detected values from 3 up to 3.45GHz.

Geekbench 5

Kind c5.large c5a.large
Single score 934 909
Single Integer 902 815
Single Float 949 969
Single Crypto 1267 1782
Multi score 1115 1168
Multi Integer 1049 1067
Multi Float 1200 1256
Multi Crypto 1470 1952

From a Geekbench perspective, C5a excels especially in cryptography realm which is not a subject to underestimate, nowadays encryption is something used everywhere, from volumes to HTTP connections or with any backend. Other domain are also more efficient but not with a huge gap.

sysbench RAM

c5.large c5a.large
Read 8201 9139
Write 6134 7091

RAM bandwidth is a good indicator of neighborough’s noise and as C5a has just been released its value has higher chance to be better. Then, we’ll also check regularly if C5 and C5a can still pretend the same throughput.


Viewing the results below and knowing instances’ prices are 10% lower, it’s not a surprise that C5a has better profile in terms of performance per dollar spent.

Type Hourly Monthly Multi score Perf/price ratio
c5.large 0.085 62.05 1115 17.97
c5a.large 0.077 56.21 1168 18.82

Monthly price is calculated from 730 hours.
Perf/price ratio equals “Mult-score / Monthly”


With this new original CPU model, AWS decreases their pricing again but with some performance increasement. In the past with the previous C5, we observed a lot of performance variation and it wouldn’t be a surprise if future tests pull the average performance up or down.

As the full series cannot be described by its smaller instance type, we also tested bigger flavors. Feel free to consult their performance on our Public Cloud Reference.