Understanding USB-C Bandwidth and Its Limits
USB-C has multiple generations and specifications that don't always work together as expected:
USB 3.2 Gen 1 (5Gbps) — The baseline for hubs with multiple outputs. A USB 3.2 Gen 1 hub that drives a 4K display, ethernet, and multiple USB-A ports is bandwidth-constrained — all those devices share the 5Gbps connection. In practice, this means slower file transfers when multiple devices are active and potential display flicker when driving high-resolution displays alongside data transfers.
USB 3.2 Gen 2 (10Gbps) — Better headroom for multiple high-bandwidth devices. A 10Gbps hub with a 4K display output and a USB-A SSD is more usable than a 5Gbps hub for the same configuration.
USB4 (20–40Gbps) — The current top specification. 20Gbps is widely available; 40Gbps is the full specification. USB4 hubs support DisplayPort Alt Mode andThunderbolt 4 Pass-through, and handle multiple displays, high-speed storage, and power delivery simultaneously without the bandwidth contention that affects lower-spec hubs.
The hub bandwidth math — If a hub uses a 5Gbps connection to the laptop and you connect a 4K display (approximately 12Gbps required for 60Hz 4K), the display runs at 30Hz or the hub falls back to lower resolution. Any hub that advertises 4K output at 60Hz must be using at least USB 3.2 Gen 2 (10Gbps) or USB4 — verify this spec before buying.
Display Output: What Your Monitor Needs
DisplayPort Alt Mode vs. HDMI Alt Mode — Some USB-C ports support DisplayPort Alt Mode (DisplayPort video output via USB-C); others support HDMI Alt Mode (HDMI output via USB-C, requiring an active HDMI adapter chip). USB-C ports that support DisplayPort Alt Mode are more versatile — they can output to any DisplayPort display with a passive USB-C to DisplayPort cable or adapter. USB-C ports that only support HDMI Alt Mode require an active adapter for anything that isn't HDMI.
Dual display capability — Driving two displays simultaneously from a USB-C hub requires sufficient bandwidth and a hub with two video outputs. Many cheaper hubs include both HDMI and DisplayPort ports but only have the bandwidth to drive one display at full resolution. A hub that supports dual 1080p displays at 60Hz is the practical minimum for dual-monitor setups.
Resolution and refresh rate tradeoffs — A hub that supports "4K" output may only support 30Hz at 4K, which is unwieldy for text work. For a primary display used for office work, 60Hz at 4K requires a hub with USB4 (20Gbps+) and DisplayPort 1.4 or later. For a secondary display used primarily for reference, 30Hz at 4K may be acceptable.
Power Delivery Passthrough
USB-C hubs that accept power input and pass it through to the laptop (power delivery passthrough) let you charge your laptop while using the hub. This is essential for most setups:
PD input ratings — Hubs accept power input at various wattages: 45W, 60W, 85W, or 100W. The input rating must be at least equal to your laptop's power requirement to charge while operating under load. A 45W hub won't charge a laptop that requires 65W — the laptop will slowly discharge while in use even when plugged in.
PD passthrough vs. fixed power — Some hubs offer passthrough charging (connect your laptop's charger to the hub, the hub feeds power to the laptop and also powers its own circuits). Others have a fixed power adapter that powers the hub but doesn't pass through to the laptop. Passthrough is more convenient; fixed power is more reliable for high-power devices. Verify which model you're buying.
The upstream port power budget — When a hub is using a single USB-C connection to the laptop, the total power available to all downstream USB ports and the hub's own circuits is limited by the upstream connection's power budget. A hub with 100W PD input might only deliver 85W to the laptop and 15W to all downstream ports combined. This is often not enough to drive high-power devices (fast-charging phones, bus-powered drives) simultaneously with laptop charging.
Hub Form Factors
Compact (puck/dongle form factor) — Small, lightweight, and portable. Typically 5–7 ports. No cable management needed. Good for travel and hot-desking. The trade-off: usually no ethernet, lower power delivery, and limited display outputs. Anker 622, Targus USB-C Compact Hub.
Standard desktop hub — Larger enclosures with better thermal management, more ports, and higher power delivery. Better for permanent desk setups. Typically include ethernet, multiple video outputs, SD card slots, and higher-wattage PD. CalDigit TS4, Anker 777, Kensington SD4700+.
Docking station vs. hub — Docking stations are a distinct category that replace the laptop's charger and provide full desktop functionality. They typically offer higher power delivery (85–100W), multiple display outputs, ethernet, and multiple USB-A ports. The distinction from a hub: a docking station typically has its own power adapter and is designed for permanent installation rather than portability. If you need to leave the desk, a hub is portable. If the laptop stays on the desk, a dock is more robust.
What to Buy by Use Case
Best for travel and hot-desking
The Anker 622 (USB-C, 7 ports, 45W PD passthrough, 4K at 60Hz via HDMI) is the practical travel hub. It includes a foldable USB-C cable, powers most ultrabooks adequately, and is small enough to fit in a laptop sleeve. For MacBooks with M-series chips, the Apple USB-C Digital AV Multiport Adapter is functional if limited.
Best for dual-monitor home office
The CalDigit TS4 (18 ports, 98W PD, dual 4K at 60Hz) is the professional-standard desktop hub. It has the thermal management to run all ports continuously, the power delivery to charge any laptop at full speed, and the port count (4x USB-A, multiple USB-C, ethernet, SD) to support a full desktop configuration. At $300, it's expensive but it's the hub that professional users buy when they want one hub that works without compromises.
Best value mid-range hub
The Anker 777 (USB-C, 8 ports, 60W PD, dual 4K at 60Hz via dual HDMI) is approximately $100 and covers 90% of what most users need. The USB-A ports are on the front, which is awkward for permanent desk installation but fine for a hub you occasionally move.
The Bottom Line
The hub you need is determined by your laptop, your monitors, and your power requirements. Buy for your specific configuration — a $300 professional hub is overkill for someone with a single 1080p monitor and no power-hungry peripherals, and a $30 travel hub is inadequate for someone who needs dual 4K displays and 85W laptop charging.
The spec to verify before any purchase: your laptop's USB-C port bandwidth and power delivery specification, your monitor's input (HDMI or DisplayPort), and the maximum resolution and refresh rate you need to drive. Then match the hub's specs to those requirements. "USB-C Hub" is not a sufficient description — the port count tells you nothing about what it actually supports.