Dell Latitude E6230, Windows 7, 82579LM, and NT Kernel and System

I have an otherwise functioning install of Windows 7 64bit edition. Sometimes, the process NT Kernel & system jumps to 20-30% from its usual 0. I can sometimes go a week without it happening. Sometimes, it's an hour. It goes away if I reboot. It also goes away permanently if I disable the 82579LM network card. So, that's the problem.

I've tried the Dell drivers, the last 2 or 3 versions of Intel drivers, and it still occurs. I've also tried virus and malware scans. Anybody have an idea how to fix it? It's not a huge deal, but I'd still like to fix it.