Thanks,
@mickevh for the usual quality explanation
In terms of hows this applies to you
@kingsize there are a number of issues that apply to your setup and unfortunately, the news might not be what you want to hear
Let's take powerlines, I am not a fan of them as I am sure that
@mickevh will attest to. The real-world speed of a powerline is not anything close to the "marketed speed". The biggest issue is that they quote the duplex speed, so the combined up and download speed so you can instantly half the speed. So your 1200 plugs, could only operate up to 600Mbps.
Now take the efficiency from
@mickevh's post at the top end of 55% then you are looking at around 330Mbps throughput. A real-world test of them is typically much lower in reality below 200Mbps for even the top of the range ones. Again there are some wiring dependencies but even rewiring won't necessarily fundamentally impact performance that much.
This is a real-world test of your one.
Tested! The Devolo dLan 1200+ Powerline adapter promises Gigabit speeds using two new hot home network technologies.
www.techadvisor.co.uk
Next to each on the same socket, they get a top speed of 375Mbps, so fractionally beating our earlier estimate. However, when they actually use it in an actual scenario the speed drops to 126Mbps.
I think personally powerlines advertising should be considered by the Advertising Standards Agency as if you think you are getting 1200Mbps and get nearer 120Mbps that's 10% of the advertised speed. Not sure which other adverts would get away with that, certainly, broadband can't anyway more.
Oh, and what the cockpit software suggests in terms of speed\link figures is frankly beep beep
So here is a problem your first bottleneck the link between the router and the rest of the WiFi network is going to be limited to no more than say 200Mbps on a good day and probably in the 100Mbps range the rest of the time.
Usually, with powerlines (like WiFi) it is only one device can talk at a time on the same frequencies. So you may find with 5 powerlines there is some contention, particularly if multiple devices are trying to all connect to the Internet etc.
On to WiFi, so you have gone with a fairly sensible approach in terms of trying to locate your WiFi access points to give you good coverage in the room.
Unfortunately, you have disabled 5GHz which is where the highest speeds will be obtained. On testing a connection I can get up to around 80Mbps on 2.4GHz depending on the conditions and I typically get up to around 600Mbps or so on 5GHz depending on the device and the bandwidth setting. By disabling it you have probably moved the bottleneck to this point and if you have multiple devices you will all be competing for the same bandwidth.
Ideally, if the dLAN is operating like a mesh network you should disable WiFi on the router so that one WiFi network controls all your network. This way clients can be encouraged to jump access points (it normally their choice), at the moment what you a bit of a hybrid system. That might work ok but it can introduce issues.
So this brings us back to the ISP, realistically unless you have a lot of devices on a good WiFi network and hardwired devices you are probably not going to make the full use of the bandwidth available and are probably overpaying. Unfortunately, VM are very good at doing marketing and encouraging people to upgrade. I think anything above 200Mbps you are into diminishing returns, very few individual services need that speed and you get 4 to 5 full UHD streams through that before you start to notice any issues. The internal infrastructure becomes a bottleneck, particularly around powerlines, which should not be used as any part of the home "backbone" in a VM or FTTP house.
Do you have any hardwired machines that would benefit?
So possible solutions depend on budget.
Personally, I would rip out the powerlines out and install hardwired cables. That probably won't go down well after just rewiring and presumably plastering etc.
Move as much as you can on to hardwired in some areas so that it is not competing for WiFi airtime.
Look at one of the WiFi mesh ones that people have used with VM. Typically they have tri-radios or hardwired base units.
Install something like UniFi and have WiFi Access points hardwired in.