My general experience is that when speeds of Broadband are being discussed, it is normal practice to stick to the one measure of Mbps, particularly as others have posted messages where the measures have been used wrongly.

Thank you for clarifying that you were using them correctly, the only clue being "data".

Possibly wrongly I just used the units the speeds are reported in. W10 happens to use MBps for the transfers I was attempting.

W10 shows the connection speed as 866Mbps which accords with the laptops Wifi spec of (2x2). An Intel document suggests that I should be able to obtain a net data transfer rate of half that i.e. 433Mbps. Infact all I could get was 36MBps or 288Mbps. which is just a third of the connection speed.

The 433 is the figure to pay attention too, so really at best you got 288 out of 433.

In short Wi-Fi speeds on boxes are over egged by a big margin, the wireless may run at those speeds but by the time all the protocol/signalling overheads are taken into account you get the drop from 866 to 433

My vague understanding of that "2x2" speed is that it also is an absolute Maximum, highly dependent on other impinging aspects.

As you have apparently minimised external ones by having the laptop very close to the router, that suggests that the slow speed is either due to the physics of the various other circuits, ie the two WiFi Rx/TXs, the comms links within the router and the laptop to the other processing units - or possibly the structure of the files used in your tests.

Could the disk writing speeds be having an effect, possibly with small buffer sizes?

I am not really "au fait" with such aspects; and it would be interesting if others with greater knowledge or also with similar/comparable gear to yours, would comment on their experiences.

In reply to a post by eckiedoo:

Could the disk writing speeds be having an effect, possibly with small buffer sizes?

The laptop has an SSD, I presume that it is an M2 type. Copying a file from one partition to another, the speed starts quite fast then slows to 80MBbps or so. The write speed of the SSD could be a contributory factor.! I don't have any other 802.11ac equipment to compare.

80MB/sec is 640 Mbps (Mega bits per second) so don't see how that is slowing you down...

In short going fast on Wi-Fi is not easy unless all kit uses standards and supports all the speed options e.g. MIMO etc

One issue with some Wi-Fi on laptops/PC can be they rely on a USB interface, rather than faster buses (this can even apply for internal devices)

In reply to a post by MrSaffron:

80MB/sec is 640 Mbps (Mega bits per second) so don't see how that is slowing you down...

It may depend on to what extent the Windows copy is a read then write operation. If you copy a large file between two partitions the copy appears to run quickly to start with as some buffer is built up and then slows down as the buffer has to be cleared before the next block is read. What I really need is a program that will read data from my NAS and then tell me the speed it is coming without bothering to do anything with the data.