When I got my new Internet Service, with advertised speeds up to 1000 Mbps, there was an immediate problem where I was getting only 30 Mbps using Windows 10 on my 2017 iMac. If I boot Mac OS on the same computer then I get up to 660 Mbps, which is more than I expected. You never get the full advertised speed anyway
, especially over Wi-Fi.
AT&T customer service couldn't do much more than verify that the service is working. They recommended that I do a Windows Update, which didn't help and took a really long time, and I also tried reinstalling the Bootcamp drivers which helped a little.
Apparently, this is a well-known problem with the Broadcom 802.11ac Wireless Adapter Windows 10 driver on the iMac. I tried to follow the advice on many websites and videos, most of which didn't work. However, I did get the speed up to about 200 Mbps, although it was frequently less. Last night I noticed that the speed was only about 80 Mbps, which I found very disappointing.
So last night I tried a different approach. I used a program called "Driver Easy" which claims that it can update all your drivers for you automatically. People recommend that you shouldn't update your drivers unless you are having a problem because you risk breaking your computer, but I was definitely having a problem. Normally, Windows 10 will update your drives for you when it does a Windows Update, although the driver that Microsoft gives you for the wireless adapter doesn't work very well on the iMac.
The Driver Easy program will download the latest driver software, but it won't install it for you unless you pay for the program. If you don't want to pay, then
it gives you clear instructions on how to install the driver yourself, which was easy for me since I already knew how to do this.
So after updating the driver with Driver Easy, I was getting speeds over 400 Mbps, which is quite adequate. If I want higher speeds then I most likely would have to run an ethernet cable from the computer to the router directly and not use Wi-Fi.