ARRIS SURFboard S34 DOCSIS 3.1 Multi-Gig Cable Modem, 2.5Gbps + 1Gbps Ethernet Ports, Compatible with Xfinity, Cox & Spectrum, Next Gen Upstream

To answer rwit. The s34 has mid/high split (500mbps/1.7gbps) currently some providers are provisioning for 200mbps on the mid split but non of them have utilized high split yet and probably never will with docsis 4 currently rolling out and planned to have full coverage in 2026. The s33 uses sub-splitting which has a limit of 100mbps upload that most cable companies only provision 10-35 mbps on sub-splitting. So glancing at the quick specs on this page I can see ones confusion when they cant read "Next Generation Upload Speed Optimized" under the features section. That is not present on the s33 features.

The arris S34 works with higher upload speeds, but can overheat if it is not placed in a well ventilated area. This can cause intermittent network issues. Be sure to place it in a space with good air circulation to avoid overheating. The S34, like most Arris products, is reliable and will perform well for years, just watch out for the extra heat that this device generates due to the additional OFDMA channels that are available. Even the coaxial cable will get very warm since this device is constantly on. Setup is easy and will work with xfinity since that is what is available in the area. When it works, it works very well. Be patient if it does not and be sure to work with your isp as needed to get any physical issues with the coaxial cable resolved. Often the problem will be outside the home since the cable is exposed to the elements outside.