Ethernet causes kernel_task to spike cpu? 10.8.2

[Saturn1217]

I just upgraded from Lion to ML after the 10.8.2 update. I did a clean install manually reinstalling all my software. So far I like the new OS a lot but I am having one issue.

At work when I use ethernet there sometimes it causes the kernel_task in activity monitor to spike to ~20% cpu usage. Not horrible but it heats up my computer and if i'm doing something cpu intensive it gets in the way.

I couldn't figure out what was causing it but I think now I have it narrowed down to when ethernet is plugged in. However it isn't consistent. I'm at work right now with ethernet plugged in and everything is normal. But when kernel_task does start acting up unplugging the ethernet stops it and when I plug it back in the kernel_task starts up again.

I've attached a screen shot of the console. Highlighted in blue is what happens directly after I plug in the ethernet cable and the kernel_task cpu usage spikes.

This isn't a deal breaker problem but it is really annoying and if anyone has any insights i'd love to hear it.

Thanks!

 

[nicklad]

What do you mean by 'using Ethernet'. Have you checked how many packets are being sent and received on the wired interface when you observe such a spike?

 

[Saturn1217]

By using ethernet I mean having the ethernet cable physically plugged in. the moment I pull the cable out the kernel_task (if it is misbehaving at the time) will immediately return to normal.

I'm not at work right now so I can't test it but I will try to look out how many packets I'm sending/receiving. Thanks.