Using PerformanceCounter to track memory and CPU usage per process?

I think you want Windows Management Instrumentation.

EDIT: See here:

Measure a process CPU and RAM usage

How to get the CPU Usage in C#?

For per process data:

Process p = /*get the desired process here*/;
PerformanceCounter ramCounter = new PerformanceCounter("Process", "Working Set", p.ProcessName);
PerformanceCounter cpuCounter = new PerformanceCounter("Process", "% Processor Time", p.ProcessName);
while (true)
{
    Thread.Sleep(500);
    double ram = ramCounter.NextValue();
    double cpu = cpuCounter.NextValue();
    Console.WriteLine("RAM: "+(ram/1024/1024)+" MB; CPU: "+(cpu)+" %");
}

Performance counter also has other counters than Working set and Processor time.

If you are using .NET Core, the System.Diagnostics.PerformanceCounter is not an option. Try this instead:

System.Diagnostics.Process p = System.Diagnostics.Process.GetCurrentProcess();
long ram = p.WorkingSet64;
Console.WriteLine($"RAM: {ram/1024/1024} MB");