If you are running CGI applications or ISAPI extensions, you can use Performance Monitor to monitor the effect of these processes on your server.
Use the Performance Monitor counters in IISProc.pmw, IISMem.pmw, and IISDyn.pmw to measure processor and memory use on the server during periods of very high or very low CGI or ISAPI application activity. Log these counters while running one of the following tests:
Monitor the effect of a CGI application or an ISAPI extension on overall server performance.
Monitor the server while running with, and then, without the CGI or ISAPI application. Log the counters for several days under similar conditions. Next, compare the rates of processor use, the average length of the processor queue, the number of available bytes, and the rate of page faults of the "with application" and "without application" tests. The difference between the values should be due to performance and memory overhead of the application.
Compare the effect on your server of equivalent ISAPI and CGI applications.
If you have ISAPI and CGI scripts that generate the same pages, you can use IISProc.pmw, IISMem.pmw, and IISDyn.pmw to compare ISAPI and CGI performance. Log server performance while the server is running one application and then log server performance while the server is running the other application. Classify the data based on the average number of requests to the application during each period. Then, compare the values of the counters during periods when the rates of CGI and ISAPI requests were similar.