So what's likely the cause of such behavior? A bad driver? Any way to find out which? Clearly, based on how sluggish my system is the CPU is at 65% even though the process window shows only the idle ...

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If I goto the task manager it says there is a process called "system idle process" and it is always at 95-100% cpu usage. However, if I look at the graph of cpu usage it shows that it is only at like ...