I have a the following gear
If I get the speed beside the Nest router I get a good 500+mb. But I am only getting 80-100 at the points. If I run a test mesh all devices have "Great Connection". I would have assumed I should be getting far higher speeds from the points if the network check is saying the connections are great.
The house has 2 floors, the main router is on one floor and the 2 points are on the other floor. Both points are only about 6M from the router & there is concrete between all points. But as I said, the mesh test says the connections are great
I'm a little surprised you're managing to get a "great" mesh connection rating with concrete obstructing the paths. In any case, it's important to understand that there's a single 5GHz radio in these units. That radio is used to carry traffic between them via a (hidden) mesh network. But, that same radio is also used to talk directly to 5GHz WiFi client devices. So, any traffic from those devices that are connected to a secondary (i.e., either your Nest WiFi Point or your Google WiFi unit) will be going through that radio twice. That means it's going over the same channel twice. If that client is close to one of the mesh secondaries, that data may be transmitted at a very high rate. But, then the mesh unit has to retransmit it back over the same channel at a lower rate that can get through the concrete to the primary/router unit. We can model the expected end-to-end throughput as something like 1/end-to-end = 1/client-to-secondary + 1/secondary-to-primary. Plugging in some typical numbers, if client-to-secondary is around 400Mbps and secondary-to-primary is around 120Mbps, then we would estimate the end-to-end would be around 92Mbps, which sounds like about what you're seeing.
You can get more details by going to the Google Home app and finding one of the devices you're testing with, opening the details screen for it, and switching to the "info" tab. First, verify that device is actually connected to the access point you expect (that's another complex discussion). Then scroll down and take a look at the three numbers under "Device Speed". The top number in that list is how fast your primary/router unit can talk to the internet. The middle number in that list is how fast that mesh/secondary unit was able to talk to the primary during the most recent mesh test. The bottom unit may not be filled in until you run a device speed test (the "Test device speed" button just below that), but it is how fast that device can talk directly to the access point it is currently connected to.
Interpreting the middle number can be tricky, since that test is running for all mesh/secondaries simultaneously, so it's not necessarily the speed you'd get when only one unit is carrying traffic. But, it's still a good way to compare different unit placement options against each other.
I hope some of this extra detail helps. Mesh networks like this are great for expanding useful coverage area, but they often do that by sacrificing peak performance in some areas for larger useful coverage.
Thanks MichaelP for the very detailed response.
I have been moving around the points to try improve peak speeds, this has give a small improvement, but not much.
I have run several mesh tests and they always return great connection. I also checked on device where I am getting 90-100mbps. The info tab had the following
524 Mbps Internet Speed
138 Mbps Wifi point speed
362 Mbps device speed (I ran a speed test)
I would have thought the 138 would be far higher. There is now no concrete between that point and the router. There is wood but not much.
The 362 is the speed between my device and the access point, that does have a more physically between it than the router to the access point, but the speeds from the device to the access point appear to be much faster.
Also, can you tell me could the height be causing an issue? The router is about 4M higher than the access point? does it broadcast out in all directions? (vertical and horizontal) ?
1/(1/138 + 1/362) ~= 100Mbps, so those numbers don't surprise me.
Keep in mind that with distance and obstruction, the achievable throughput goes down quickly. The raw signaling rate might be 866Mbps without obstructions at a few feet of distance, but put a few meters and a few walls/floors in between, and that will drop quickly to 200-250Mbps (and that's before accounting for the relatively high WiFi overhead). Concrete will definitely hit this harder (as will brick, plaster, ceramic tile, metal, etc.), but even wood isn't transparent to RF. WiFi is pretty low transmit power in general.
As for your closing question, the units have omnidirectional antennas (roughly spherical pattern). So, orientation and relative heights shouldn't matter. But, where height can be important is getting the access points up above obstructions like furniture, especially metal appliances, bookshelves, etc.