Arris Surfboard S34 Cable Modem | DOCSIS 3.1 & Next-Gen Speed

The Arris SURFboard S34 is a DOCSIS 3.1 cable modem built for multi-gig download plans and the faster upload tiers cable providers are now rolling out. It pairs a 2.5 Gbps Ethernet port with switchable mid-split upstream support, which makes it one of the few retail modems on Xfinity's Next Gen Speed Tier list. Own it, and the equipment rental fee comes off your bill for good.

Quick Specs

Next Gen Upload Speeds

Most cable modems, including the popular Arris S33, are limited to the narrow low-split upload band that keeps uploads around 20 to 40 Mbps no matter how fast the download plan is. The S34 adds switchable upstream filters that let it operate in mid-split mode where the provider has upgraded the network. On those plans, uploads jump into the hundreds of megabits, which changes the experience for video calls, cloud backups, and live streaming.

The S34 is on Xfinity's Next Gen Speed Tier list. The S33 is not. If your Xfinity plan advertises uploads of 100 Mbps or more, the S34 is the Arris modem that will deliver them. On plans without enhanced uploads, it performs the same as the S33 and falls back to low-split automatically.

Multi-Gig Ethernet Ports

2.5 Gbps port

Connect this to a router with a 2.5 Gbps WAN port to pass the full speed of a 1.2 Gbps or 2 Gbps plan. A router with only a 1 Gbps WAN port will cap the connection around 940 Mbps, so check the router before upgrading the modem.

1 Gbps port

A second port for a wired connection to a gaming PC, console, or a second router. The two ports do not combine into one faster connection; the second port only carries traffic if your provider assigns a second IP address, which most do not.

Design and Heat

The S34 uses a compact white vertical case that fits on a shelf or desk. It runs warm. The mid-split OFDMA channels generate more heat than the S33's, and owners who tuck it in a closed cabinet or stack a router on top report dropped connections. Give it a few inches of open air on all sides and it runs reliably for years.

What's in the Box

• Arris SURFboard S34 cable modem
• Power supply
• Quick start guide

Compatibility

The S34 is a cable-only modem. It does not work with DSL, fiber, or satellite internet, and it does not carry phone service.

• Xfinity: Approved for all plans up to 2 Gbps download and listed on the Next Gen Speed Tier list for enhanced uploads. It is the right choice for Xfinity plans that advertise uploads above 40 Mbps.
• Spectrum: Approved for plans up to 1 Gig. Mid-split uploads engage only in markets where Spectrum has completed its upstream upgrade.
• Cox: Listed for plans up to 2 Gbps. Cox's enhanced upload rollout has been slower than Xfinity's, so the mid-split feature is mainly future headroom for Cox customers today.
• Other providers: Confirm the S34 appears on your ISP's approved modem list before purchasing. Approved lists change several times a year.

Why Buy from ModemGuides

Every S34 we sell is tested, cleaned, and covered by a 90-day full-coverage warranty. It also carries our activation guarantee: if your provider will not activate it on a plan it is approved for, we make it right. Buying refurbished from a specialist gets you a proven unit at a fraction of the retail price, and the modem pays for itself in rental fees within a few months.

Frequently Asked Questions

What is the difference between the Arris S33 and S34?

Downloads, ports, and chipset are the same. The S34 adds mid-split upstream support for enhanced upload tiers. If your plan does not include faster uploads, the S33 performs identically for less.

Does the Arris S34 have WiFi?

No. It is a standalone modem. Pair it with a router or mesh system that has a 2.5 Gbps WAN port to get full multi-gig speed.

Does the S34 work with Xfinity's Next Gen speed tiers?

Yes. It is one of the modems on Xfinity's Next Gen Speed Tier list, which is required for the enhanced upload plans.

Does the Arris S34 run hot?

It runs warmer than the S33. It is stable with open air around it. Avoid closed cabinets and do not stack a router on top of it.

How do I set up the Arris S34?

Connect the coax cable, plug in the power supply, and connect the 2.5 Gbps port to your router. Then activate it through your provider's app or activation page. Most activations complete in a few minutes.