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

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

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        "polar": true,
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    },
    "credits": {"enabled": false},
    "title": {"text": ""},
    "xAxis": {
        "categories": ["Single score", "Single Integer", "Single Float", "Single Crypto", "Multi score", "Multi Integer", "Multi Float", "Multi Crypto"],
        "tickmarkPlacement": "on"
    },
    "yAxis": {
        "gridLineInterpolation": "polygon",
        "lineWidth": 0,
        "min": 0
    },

    "tooltip": {
        "shared": true,
        "pointFormat": "{series.name}: {point.y:,.0f}"
    },
    "series": [{
        "name": "c5.large",
        "data": [934.748, 902.366, 949.532, 1267.012, 1115.760, 1049.437, 1200.413, 1470.049],
        "color": "#f7981c",
        "pointPlacement": "on"
    }, {
        "name": "c5a.large",
        "data": [909.750, 815.139, 969.257, 1782.650, 1168.501, 1067.416, 1256.787, 1952.900],
        "color": "#036875",
        "pointPlacement": "on"
    }]
},"hc_type":"chart","id":"140417476574680"}

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

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    "credits": {
        "enabled": false
    },
    "title": {"text": ""},
    "xAxis": {
        "categories": ["Read", "Write"]
    },
    "yAxis": {
        "min": 0,
        "title": {"text": "In KB/sec"}
    },
    "series": [{
        "name": "c5.large",
        "data": [8201.827, 6134.674],
        "color": "#f7981c"
    }, {
        "name": "c5a.large",
        "data": [9139.849, 7091.097],
        "color": "#036875"
    }]
},"hc_type":"chart","id":"140417476574681"}

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.

Performance/Price

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.

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

Conclusion

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.