svchost is a host process for Windows tasks & Services. Go into task manager and go into processes, Sort by CPU usage. If you see any svchost taking any CPU, right click it and click "Go to Services" this should open the Services Tab of Task Manager, with the Services set to that process, highlighted in blue.
That means one of those services is using CPU. If Windows Update is in that list, it's probably that one.
Also, I would pay attention to any process using Disk (I/O) as processes that spike in that are normally cause of some lag spikes, skips, whatnot. Normally Antivirus & the lot are the cause of Disk usage spikes and game lag.