Some very quick tests showed a very apparent performance increase:
Platform: 300Mhz Pentium MMX (Sony Vaio PCG-505TR), FreeBSD Program: A script that first imported the standard library cgi module, then output a single word "Hello!". Measuring tool: ab (included with apache), 1000 requests. Standard CGI: 5 requests/s Cgihandler: 40 requests/s As a handler: 140 requests/s