I have a new broadband plan of 1000 Mbps been effective for a few days. With a new ac router claiming a max to 1300 Mbps, I have conducted a brief test with my SE. It was at 267 Mbps, far lower than I expect. I am going to test it with an iPhone 6s which may benefit with MIMO. What is the top WiFi speed that iPhone 6s supported?
All iPhone 6s models support 802.11a/b/g/n and ac Wi‑Fi with multiple input multiple output (MIMO).
The iPhone SE also supports 802.11a/b/g/n and ac Wi‑Fi (but without MIMO).
While you should get better speeds with the iPhone 6s, the reality is that there are many factors that can impact speed at any given point of time.
However, if my reading of your question is correct, I think it's based on a misunderstanding of what the ac router claiming a max speed of 1300 Mbps actually means. This 1.3Gbps (1300Mbps) figure can be highly misleading because it is a theoretical maximum. It translates to 166 megabytes per second (MBps) or about 1331 megabits per second (Mbps), which of course sounds fantastic, but these figures are never realised in real world scenarios.
Most 802.11ac routers will perform closer to a range of 250-300Mbit.
In terms of your devices, you'll find that the speed obtained by 802.11ac capable devices will differ considerably depending on how many antennas they can physically fit in. While the maximum supported by the 802.11ac standard is 8 antennas, most smartphones only have 1 antenna, most tablets will have between 2-4 antennas, and so on. Even 802.11ac routers will differ in terms of how many antennas they will incorporate.
If you are using a device that is 802.11n you will max out at about 450mbps as you will be on the 2.4ghz wifi signal, 5ghz wifi signal which will use 802.11ac will max out at 1.3gbps depending on your service.
We just had AT&T come install their 1000 Mbps fiber internet today.
They provided an Arris BGW210-700 gateway (router).
I was curious to first test just the speed of the wifi connection between the router and my iPhone 6S (i.e. ignore the speed of the WAN/fiber).
I used the Wi-Fi SweetSpots app and saw speeds from 429 to 478 Mbps.
I currently have no devices that can plug directly into the gateway, so I can't test whether AT&T is actually supporting the full 1000 Mbps download and upload speeds (but clearly my iPhone would be the bottleneck on the speeds anyway)†.
When I tested my phone's internet connection through the router (using http://www.speedtest.net/mobile), I saw download and upload speeds ranging from 322 to 456 Mbps.
† The Arris BGW210-700 gateway itself has a speed test and claims that it is achieving 974 Mbps download and 938 Mbps upload.