CPU Bottleneck Symptoms

Symptoms for CPU bottlenecks include the following :

The Processor(_Total)\% Processor Time(measures the total utilization of your processor by all running processes) will be high. If the server typically runs at around 70% or 80% processor utilization then this is normally a good sign and means your machine is handling its load effectively and not under utilized. Average processor utilization of around 20% or 30% on the other hand suggests that your machine is under utilized and may be a good candidate for server consolidation using Virtual Server or VMWare.

Further to breakdown this %processor Time , monitor the counters - Processor(_Total)\% Privileged Time and Processor(_Total)\% User Time, which respectively show processor utilization for kernel- and user-mode processes on your machine. If kernel mode utilization is high, your machine is likely underpowered as it's too busy handling basic OS housekeeping functions to be able to effectively run other applications. And if user mode utilization is high, it may be you have your server running too many specific roles and you should either beef hardware up by adding another processor or migrate an application or role to another box.

The System\Processor Queue Length(indication of how many threads are waiting for execution) consistently greater than 2 or more for a single processor CPU is a clear indication of processor bottleneck . Also look at other counters like ASP\Requests Queued or ASP.NET\Requests Queued as well.