This morning, my iMac started to slow down significantly, whereas my MBP was doing just fine. By slowing down, I mean spinning beach balls, Numbers took 5 minutes to open, the app store was not reachable and a reboot took 25 minutes rather than the usual 2. Hardware diagnostic, cleaning all logs, flushing DNS cache, antivirus, nothing helped. When running recovery, I could go to Apple.com, but could not get to download Mojave to reinstall it.
So I contacted Apple. 3 chat sessions, 1 phone call and 3 hours later, nothing.
And then I noticed my second Mac slowing down after terminating the company VPN. Pinging Google and other major sites still worked, nothing else did. I called Comcast and 45 minutes later they admitted something was wrong on their servers. A tech will be coming on Friday to check out my connections.
All the while, my iPad on WiF was doing relatively fine. No slowdowns at all, just some sites I could not reach. Whereas my Macs on Mojave are super slow, many apps cannot even be launched. Any idea why that could be the case?
My guess is mostly just because iOS was designed with the idea of no or limited Internet available but macOS assumes that you always have fast, unlimited Internet.
Thanks, TJ - I thought so, too, at least initially. In fact, when I disconnect my IMac from the network, it’s as snappy as ever. Only if connected does it become so slooooooow. As if internal services have very long timeouts, and these services are stacked on top of each other. No excessive CPU usage by any service though. I suspected iCloud Drive, since heavy activity on iCloud Drive often slows things down, but no, does not seem to be the case.
I think that’s the other side of the same coin - if there’s no network, macOS can deal with that. It’s just limited network that it has trouble with, because the OS was designed for big unlimited Internet pipes.
Are you sure you’re not experiencing a network / DNS issue? It sort of looks like the network is flooding (a DNS/Broadcast storm or something like that?) which is spreading through the wired network first and is only slightly affecting the wifi? or am I reading it wrong?
I’ve seen this happen when a switch goes bad, or IOT devices need a restart.
Thanks, @JKoopmans - it’s not the network flooding. In fact once Comcast confirmed it was their problem and I could reproduce that using our corporate VPN (where are no problems when connected, and massive slowdown, when disconnected, and no problem, when the network is turned off), I installed a VPN on my personal Macs and they are back to their usual zippy selfs. I’ll keep on the VPN until they come back. Another reason to have a VPN as a backup…
Many/most macOS/Windows applications like Microsoft Excel routinely try to connect to multiple servers every time you open them. As I recall, the last time I monitored Excel it routinely connected to 16.
Mobile is a different environment. My guess is IOS developers have to consider our iPhones and iPads have less power and bandwidth available when they design their apps.