For moving big files across your own network, a wire almost always wins — but the gap is smaller than it used to be, and modern Wi-Fi is genuinely good enough for a lot of what people do. Here's how to tell which side of that line you're on.

Why the two behave so differently

Ethernet and Wi-Fi solve the same problem in opposite ways, and the differences explain everything else.

A wired Ethernet link is full-duplex: it can send and receive at full speed simultaneously, over a dedicated pair of wires that nothing else shares. The connection is a private tunnel between your device and the switch. Latency is low and steady, and the negotiated link speed — 1 Gbps, 2.5 Gbps — is a ceiling you can nearly reach in practice.

Wi-Fi is half-duplex and shared. The airwaves are a single conversation that every nearby device has to take turns using. Your laptop, your phone, your neighbor's access point, and a microwave oven all compete for the same spectrum. Only one device can transmit on a channel at a time, so airtime is divided among everyone, and each retransmission from interference eats into the total.

The advertised-speed trap

The single most misunderstood thing about Wi-Fi is the number on the box. When a router claims "AX3000" or "5400 Mbps," that's the PHY rate — the theoretical signaling rate under laboratory conditions, summed across every band. Real-world throughput — what a file transfer actually achieves — is typically only 40–60% of the PHY rate, and often less at range.

That overhead isn't a defect; it's the cost of doing wireless. Protocol management, the half-duplex turn-taking, error correction, and retries all consume airtime that never carries your file. So a laptop showing a "1200 Mbps" Wi-Fi link might deliver 500–700 Mbps of usable throughput up close, and much less across the house. Ethernet has overhead too, but it's small and predictable: a gigabit link reliably delivers ~940 Mbps.

Real-world comparison

	Gigabit Ethernet	Modern Wi-Fi (Wi-Fi 6, 5 GHz)
Typical real throughput	~940 Mbps, consistent	~400–700 Mbps close, dropping with distance
Latency	Sub-millisecond, stable	2–10 ms, variable; spikes under load
Consistency	Very high — same every time	Fluctuates with interference and clients
Best use	Backups, NAS, gaming, desktops	Laptops, phones, tablets, roaming devices

Large file copies and backups

This is where wired pulls clearly ahead. Copying a 50 GB video project to a NAS over gigabit Ethernet finishes in around nine minutes at full speed. Over Wi-Fi, the same job might take two to three times as long, and the rate will sag and surge as conditions change. For a nightly backup that has to complete unattended, the consistency of a cable matters as much as the peak speed. If your transfers to network storage feel slow, our guide on the causes of slow NAS transfers walks through the usual suspects.

Gaming and latency

For competitive gaming, latency and its variation (jitter) matter more than raw throughput. A wired connection gives you a steady sub-millisecond local hop and no airtime contention, so your inputs arrive on a predictable cadence. Wi-Fi adds a few milliseconds on a good day and occasional spikes on a bad one — usually fine for casual play, noticeable in fast-twitch titles. Our guide on throughput, latency, and jitter explains why the smoothness of a connection isn't the same as its speed.

Everyday browsing and streaming

Here Wi-Fi is not just adequate — it's the right tool. Streaming 4K video needs around 25 Mbps; a video call needs a few. Both sit far below what even mediocre Wi-Fi delivers, and the convenience of no cable wins easily. Throwing Ethernet at a tablet that only browses is effort spent solving a problem you don't have.

When Wi-Fi is "good enough"

• The device moves around, or running a cable to it is impractical.
• Its heaviest task is streaming, video calls, browsing, or light cloud sync.
• It sits reasonably close to the router or an access point on the 5 GHz or 6 GHz band.
• You're not moving tens of gigabytes across the LAN on a schedule.

Modern Wi-Fi generations have narrowed the gap considerably; a good Wi-Fi 6 or Wi-Fi 6E setup handles most homes' needs. See how Wi-Fi generations compare for what each standard actually delivers.

When to run a cable

• Stationary, high-traffic devices: desktops, a NAS, a home server, a media box that streams large local libraries.
• Backups and large transfers that need to finish predictably and fast.
• Latency-sensitive use: competitive gaming, low-latency audio/video work, remote-desktop sessions.
• A crowded RF environment — an apartment building where dozens of networks fight over the same channels.

Don't forget the cable itself

Going wired only helps if the cable can carry the speed. Cat5e handles gigabit fine; for 2.5G, 5G, or 10G you'll want Cat6 or Cat6a, and distance starts to matter. Our guide on Ethernet cable categories covers which category you actually need — and it's cheaper to get it right than to rewire later.

The honest bottom line

Ethernet is faster, lower-latency, and far more consistent for local transfers, and for anything stationary and demanding it's worth the cable. But Wi-Fi has genuinely caught up for the everyday tasks most devices actually perform, and its real-world throughput — once you discount the box's PHY-rate marketing — covers streaming, calls, and browsing with room to spare. Match the connection to the job: wire what sits still and moves data, let the rest roam free, and you'll get the best of both.