Counter	Description	Significance
CPU -- % processor time	The percentage of the processor time that is used to process user or system transactions as opposed to the CPU sitting idly	The higher the processor usage, the more the CPUs are being used to process user or system transactions
System -- Processor queue length	The number of threads that are waiting for the CPUs	The higher the queue rate, the more the threads are waiting on the CPUs to process the instructions on the CPU
Memory -- Pages/sec	Pages read and written from memory	The higher the memory usage, the more processes are thrashing in memory
Paging file -- % usage for _Total	The percentage of all page files that are in use	The higher the page-file usage, the more memory is needed to support the system in excess of the physical memory on the server
PhysicalDisk -- Avg. disk queue length	The number of read and write requests that are queued for the physical disk subsystem	The higher the average disk queue length, the more resources are waiting for earlier requests to finish prior to fulfilling their request
Network interface bytes Total/sec	The bytes sent and received over a single network card	Determine if excessive network traffic is occurring on a network card or if the system has issues isolated on the SQL Server with no network traffic
System -- Threads	The number of threads on the computer	Determine if the number of threads greatly exceeds the typical baseline indicating more processes are occurring on the system
System -- Context Switches/sec	The number of processes that are changing threads per second	The higher the context switching, the more the server is stressed