IPv6 Soaking Up CPU


macrumors 68040
Original poster
Jun 17, 2014
Lincolnshire, UK
All of my Macs have the MenuMeters Preference pane installed, so my CPU use is always visible in the Menu bar - with this I can see that when idling they all use between 0-2% CPU.
I just noticed that my recently acquired 15" DLSD was idling at 12-15% - trying to hunt down that missing CPU task in Activity Monitor, Console and Top in Terminal revealed nothing.
I ran Onyx to clear out caches and fix permissions etc but it still remained...then I turned Airport off....back down to 0-2%!
I suddenly remembered, had I turned Configure IPv6 off in Network Preferences like I normally do?
Sure enough, it was set to the default of Automatic - switching it off returned the CPU meter to 0-2% - worth knowing if you like to squeeze out every bit of CPU.


macrumors 6502
Nov 11, 2017
West Virginia
That's such a weird behavior! I realize that IPv6 still doesn't matter for most folks, let alone when Leopard was released, but it still seems like an obvious bug that this would eat that much CPU.


macrumors 6502a
Mar 19, 2016
North of the HellHole
IPv4 exhaustion due to more and more devices using IP adresses ( IoT) and more and more things being connected constantly to the Internet.

IPv6 uses 128 bit adresses vs IPv4 using 32 bit adresses , plus IPv6 offers a lot more LAN functionality without needing a router.