[Network] ARRIS SURFboard S33 Modem Review | Beyond Gigabit

Recently, I came across a reddit post (ref) stating combination of this modem, specific brand SFP+ transceiver and UniFi Dream Machine Pro achieved beyond gigabit on a gigabit Xfinity service. I have indeed decided to give a try on this, and the result is great.

Specification

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• DOCSIS 3.1
• Multi-gigabit Ethernet Port 2.5 Gbps x 1
• Gigabit Ethernet Port x 1
• Price $179.99

Setup

Above is my current/new network setup. Previously, I had Netgear CM1100 Modem, which is . Now I have replaced that with Arris S33. With it, my connection between modem to UDM Pro router becomes 2.5 Gbps where it used to be 1 Gbps.

My internet service provider service is from Xfinity Gigabit with 1 Gbps download and 35 Mbps upload.

Feature

I am not sure if there is much feature we should look in cable modem besides its modem function. There are modems with built in router function and Wi-Fi, but someone who is looking for S33 level of performance, I surmise one has dedicated router. So even though, there aren’t much additional feature in it, this modem has the key feature i.e. multi-gigabit ethernet port. At the moment, this alone is suffice to give excellent score for the feature.

Value

$179.99 for cable modem alone is far from cheap. However, if we look at the competitor device with the same feature i.e. 2.5 GbE port, this is far better value as Netgear version of 2.5GbE modem is priced at $249.99.

Performance

The above is one of speed test result I got on UDM Pro using UniFi Network Controller speed test.

The test above is from my Xfinity speed test using wired iMac 2020 client that has 10GbE connection via thunderbolt 3 to ethernet adapter.

These results demonstrate beyond what I have been promised by Xfinity. In fact, using Netgear CM1100 modem connected to UDM Pro via 1 Gbps link capped at 940 Mbps download speed, which is well known practical throughput cap on 1 Gigabit connection.

I have learned that the limitation is from the gigabit link between modem and router because Xfinity servicing more than they are advertising to the clients (overprovision) their service including gigabit service (ref).

Alternatives

I surmise any multi-gig port capable modem would do well here. However, there just are not that many options at the moment. Besides S33, Netgear Nighthawk Multi-Gig (CM2000) has 2.5 Gbps port ($249.99). It is currently not available to purchase at the retail price even on Netgear’s official website, but retail price is significantly higher than that of S33.

Another option is to use link aggregation to achieve speed beyond 1 Gbps. This is a technology where you can use two or more Ethernet Cables to link and act as a one. In fact, my previous modem, Netgear CM1100 supported it; therefore, I should have been able to achieve 2 Gbps from this end; however, my router (UniFi Dream Machine Pro) had no link aggregation capability. So this was not an option for me.

Conclusion

If you are looking for the best possible speed with your gigabit cable internet service, S33 is one of the best available option at the moment based on its value and multi-gigabit port.