iMac broadband connection slows down after a couple of hours
Hi,
I use an iMac (Retina 4K, 21.5-inch, Late 2015), running macOS Catalina Version 10.15.7 (19H2). I also have an iPhone and iPad but details aren't important.
The issue: my iMac's broadband connection slows down after a couple of hours of being in use. I normally get download speeds of around 100Mbps. When I (re-)start my machine, broadband connection is fine. After a couple of hours, I notice it drops to around 5Mbps. This doesn't happen to my iPhone or iPad, so I think the cause must be my iMac rather than my broadband connection. Speed doesn't change when I close certain apps.
Any advice appreciated - whether there is a known issue/cause, or if there's a way I could try to identify the cause (and then rectify!). Thanks in advance.
iMac 21.5″, macOS 10.15