On November 5, Vodafone UK announced Pro 4 Broadband, a home plan with speeds of up to 8Gbps on CityFibre's full fibre network. It comes with the Ultra Hub 7+, a tri-band Wi-Fi 7 router, and costs £32 a month. The release gives some illustrative download times: a 1GB file in around a second, and a 100GB game in under two minutes.
Eight gigabits per second is a rate. It is the capacity of the line, not the speed any one download is guaranteed to see. So what decides the number a person actually gets?
What was announced
Figures here are as stated in Vodafone's own press release. The release says the Ultra Hub 7+ can support up to 10Gbps and that up to three Super WiFi Boosters are included at no extra cost. Its footnote says the quoted speeds are maximum theoretical speeds, and that devices and download servers can affect real speeds.
That footnote is the interesting part. It names two things outside the fibre line itself that limit the result: the device and the server at the far end. There is a third that the footnote does not name but every network engineer knows: the time it takes a packet to get there and back.
Why a bigger line does not make one transfer faster
A TCP session can only have so much unacknowledged data in flight. It sends a window of data, then waits for the acknowledgment to return before sending more. The maximum rate is therefore the window size divided by the round-trip time (RTT). Bandwidth sets how much the line can hold. RTT and window size set how much one session can use.
A worked example makes the gap clear. Take a server 25 ms away. A single TCP session limited to a 64 KB window can move about 20.9 Mbps at that RTT, whether the line underneath is 100 Mbps or 8 Gbps.
Rate: 524,288 bits ÷ 0.025 s = about 20.9 Mbps
To fill an 8Gbps line at the same 25 ms, a session needs a lot more data in flight. This is the bandwidth-delay product: the rate multiplied by the RTT.
The 25 ms RTT and the 64 KB window are illustrative inputs, not measurements of Vodafone's service. Real window sizes depend on the devices at each end. The point is the shape of the arithmetic: the faster the line, the more data must be in flight to use it, and the more a small increase in RTT costs.
The last 10 meters
The router adds its own link. Vodafone describes the Ultra Hub 7+ as a tri-band design that spreads devices across more radio bands. That raises the ceiling on the in-home link, but a phone or laptop on Wi-Fi shares the air with other devices and loses signal through walls. The wired port and the wireless link can give very different results from the same line at the same moment.
This is the same question we raised for 5G home broadband in our article on which link is weak. With a fast fibre line the answer matters more, because a small fraction of 8Gbps is still a large number, and a user can mistake a Wi-Fi limit for an ISP limit, or the reverse.
What to measure
To judge a multi-gig connection, measure more than the peak:
- Sustained throughput over time, not a short burst that ends before the connection reaches equilibrium.
- RTT, and how much it varies, since TCP throughput is bounded by it.
- Consistency of Service, the minimum speed divided by the maximum over a test.
- The connection type for each result, so wired and Wi-Fi tests are not mixed together.
- Several concurrent sessions, since a household rarely runs just one.
MyConnection Server implements the RFC 6349 TCP throughput method. It measures RTT, calculates the theoretical maximum, runs sustained transfers, and reports equilibrium throughput, consistency of service, TCP window size, retransmissions and multi-session performance, so a gap can be traced to latency, window limits or loss. Its connection tests also record whether a test ran over Wi-Fi or wired Ethernet, and currently on Windows the Wi-Fi signal strength and quality. That is a quick indicator, not a Wi-Fi assessment. For the reasoning behind measuring this way, see the whitepaper on measuring high-capacity connections. The same approach applies to remote workers on home connections.
Sources: product, price, router, speed and footnote details are from Vodafone UK press release, November 5, 2026. The 25 ms RTT, 64 KB window and resulting figures are an illustrative calculation, not measured data. Accurate as of November 5, 2026.