Vivid 350. 5Ghz band reaches 350 but 2.4 only around 70Mbps max. Is this normal?
Sounds about right. Below is a breakdown of actual real-life average speeds you can expect from wireless routers within a reasonable distance, with low interference and small number of simultaneous clients:
802.11b - (2.4GHz) 2-3 Mbps downstream, up to 5-6 Mbps with some vendor-specific extensions. 802.11g - (2.4GHz) ~20 Mbps downstream 802.11n - (2.4GHz and 5 GHz) 40-50 Mbps typical, varying greatly depending on configuration, whether it is mixed or N-only network, the number of bonded channels, etc. Specifying a channel, and using 40MHz channels can help achieve 70-80Mbps with some newer routers. Up to 100 Mbps achievable with more expensive commercial equipment with 8x8 arrays, gigabit ports, etc. 802.11ac - (5 GHz) 70-100+ Mbps typical, higher speeds possible over short distances without many obstacles, with newer generation 802.11ac routers, and client adapters capable of multiple streams.
Disclaimer - I don't work for Virgin Media. I'm just another VM user trying to help out. My setup: V6 TV box, Vivid 200 Optical fibre with Hub 3 in modem mode connected to a Netgear R7000 router. Telewest/VM user since 2001.
As a Very Insightful Person, I'm here to share my knowledge. I don't work for Virgin Media.
That old Smallnetbuilder (the first place I saw it) excerpt has been around for ages, probably over a decade and a bit outdated now.
First a note on LINK speeds. The Link speed which is the theoretical speed in one direction ignoring overheads. Due to the half duplex nature of wireless, overheads and the way wireless works, actual speeds will be roughly half of the LINK speed.
Wireless N two wireless channel bonding and up to 4 spatial streams 2.4GHz and 5 GHz
Single stream 1 x 1 client 72 Mbps LINK 20 MHz wide channel. (about 40 Mbps real world) 150 Mbps LINK 40MHZ wide channel (about 75 Mbps real world) *not recommended on the narrow 2.4GHz band
Two stream MIMO 2 x 2 client 144 Mbps LINK 20 MHz wide channel. (about 75 Mbps real world) 300 Mbps LINK 40MHZ wide channel (about 150 Mbps real world) *not recommended on the narrow 2.4GHz band
The Hub has Two 2.4GHz antennae and Three 5 GHz antennae.
Wireless AC Four channel bonding and up to Eight spatial streams 5GHz only.
Single stream 1 x 1 client 87 Mbps LINK 20MHz channel. (about 50 Mbps real world) 433 Mbps LINK 80 MHz channel (about 220 Mbps real world)
Two stream MIMO 2 x 2 client 173 Mbps LINK 20 MHz wide channel. (about 90 Mbps real world) 866 Mbps LINK 80 MHZ wide channel (about 450 Mbps real world) *not recommended on the narrow 2.4GHz band
All Link speeds assume a Short guard Interval Full MCS table HERE