A box promising 3,000 or 5,000 megabits per second sets an expectation that the first speed test quietly destroys. The figure on the packaging is real in the sense that the hardware can produce it, just never in the room where you are sitting. Between that peak and the number your phone reports lies a chain of predictable deductions, each one measurable. Following a single connection through those deductions shows why a high advertised rate can honestly land at a few hundred megabits, and what a fair result actually looks like on a normal evening.
How the number on the box is built
The advertised rate is the sum of every radio the router contains, each running at its theoretical maximum. A dual-band unit labelled AX3000 reaches that figure by adding roughly 2,402 Mbps on the 5 GHz band to about 574 Mbps on 2.4 GHz, then rounding up. No single device ever connects to both totals at once, and no client uses every antenna at full modulation, so the headline is an accounting sum rather than a speed anyone receives. The ceiling each band can reach is set by the generation of Wi-Fi in play, the point the guide on how each Wi-Fi generation sets its ceiling works through.
The overhead you never see
Wi-Fi carries a great deal of traffic that is not your data. Every frame includes a preamble, headers and a guard interval, receivers send acknowledgements, and the network reserves time for management chatter. Add the TCP and IP headers wrapping your files, and a large slice of the raw rate disappears before any content moves. In practice the usable throughput of a Wi-Fi link sits around 55 to 65 percent of its physical layer rate, so a 1,201 Mbps connection realistically delivers roughly 700 to 800 Mbps at its very best. The 2.4 GHz band loses proportionally more, because it runs older, narrower channels and shares space with far more interference, so its real throughput trails an already lower headline.
One radio, many devices
A Wi-Fi radio is half duplex, meaning it either sends or receives, never both in the same instant, and only one device on a channel transmits at a time. Devices take turns using a politeness protocol that listens before speaking, so airtime is divided among everything connected. A tablet streaming video and a laptop backing up files do not each get the full link, they share it, and a distant device that transmits slowly consumes more than its share of that time. Adding devices therefore feels like everyone slowing down together rather than a clean split, since the airtime a slow phone holds is time no faster device can use. The effect shows up first in real-time traffic, which is part of why a call breaks up, the symptom the guide on what makes a video call stutter examines.
Signal strength sets the modulation
The rate two radios agree on depends on how cleanly they hear each other, measured as the signal to noise ratio. Close to the router, a strong clean signal supports dense modulation such as 1024-QAM, packing many bits into each transmission. As distance and walls weaken the signal, the radios step down through simpler schemes to stay reliable, and the rate falls in large jumps rather than a gentle slope. This rate adaptation happens continuously, which is why moving one room away can halve your throughput even though the connection still shows as connected. The router reports the negotiated link rate, not the speed of your actual transfers, so a status screen showing 866 Mbps may still move files at a third of that.
Following one connection down to a real figure
Take a Wi-Fi 6 laptop working near an AX3000 router. Here is where the advertised number goes:
- The 5 GHz radio peaks at 2,402 Mbps, but the laptop has two antennas rather than the router’s assumed maximum, so it negotiates 1,201 Mbps.
- Protocol overhead removes about 40 percent, leaving roughly 720 Mbps of usable throughput.
- Two other devices are active, so shared airtime trims the laptop’s slice to around 400 Mbps during busy moments.
- The laptop sits two rooms away, so a weaker signal drops the negotiated rate and the real figure settles near 300 Mbps.
Nothing here is faulty. A 3,000 figure on the box became 300 on the device through four ordinary steps, a tenfold reduction that every household meets in some form. A mesh hop would add a further deduction, since a second unit relaying traffic spends airtime doing so, a trade the guide on whether a mesh helps or hurts weighs carefully.
Measuring throughput without fooling yourself
An internet speed test measures the whole path out to the wider network, so it caps at your subscription and tells you little about the Wi-Fi link itself. To judge the wireless segment, run a local test with a tool like iperf3 between two devices on your own network, first with a wired reference, then over Wi-Fi at varying distances. Comparing local and internet results separates the short Wi-Fi hop from the longer route that reaches your public address, the boundary the guide on the address your router shows the world defines.
What a realistic figure looks like
A fair expectation is a fraction of the box, not a match for it. On a modern dual-band router, a close device commonly sees a few hundred megabits of real throughput, more on 6 GHz with a wide channel, and less as walls and distance accumulate. Those numbers are healthy, not broken, and they reflect the physics of a shared radio rather than a defect in your equipment.
Judge your network against what the link can plausibly carry, not against the packaging. If a device beside the router reaches a solid share of your internet plan and only fades with distance and load, the hardware is doing its job. Chasing the advertised total is chasing a number designed for a sticker, not for a room with furniture, walls and other people in it. Set the benchmark once, near the router and far from it, and you will stop measuring your network against a figure the box was never going to deliver.
Frequently asked questions
Why is my Wi-Fi slower than advertised?
The advertised figure adds every band at its theoretical peak, a total no single device can reach. Real connections lose 35 to 45 percent to protocol overhead, share airtime with other devices, and slow down as distance weakens the signal. A tenfold drop from the box number to a device is normal. Compare against your internet plan and the link’s realistic rate instead of the sticker.
What speed should I actually get?
Close to a modern dual-band router, expect a few hundred megabits of real throughput on 5 GHz, and more on a 6 GHz channel with compatible devices. Two or three rooms away, half or less is common. The right benchmark is a healthy fraction of your internet subscription near the router, tapering with distance, not the number printed on the packaging.
Does distance really affect Wi-Fi speed?
Yes, strongly. As the signal weakens with distance and passes through walls, the two radios drop to simpler, more reliable modulation, and the negotiated rate falls in steps. Moving a single room away can halve throughput even while the connection still appears full. Higher frequencies such as 5 and 6 GHz carry more data but fade faster over distance than 2.4 GHz does.
