Summary: Think twice before using System.GC functions to (try to) solve your perf problems

Avoid GC.Collect

When objects are not being collected in a timely fashion it more often indicates that you have "Mid-Life Crisis" (lots of objects that are dying just as they reach generation 2). Trying to use GC.Collect() to force collections and GC.WaitForPendingFinalizers() is much more likely compound these problems than to actually help. Instead, think carefully about your objects lifecycle, especially considering the policy of any caches you have built.

References:

*Mid Life Crisis
*Caching Policy
*Two Things to Avoid
*When to call GC.Collect

Articles related to the Garbage Collector:
*Garbage Collector Basics and Performance Hints
*Using GC Efficiently - Part 1: Fundamentals
*Using GC Efficiently - Part 2: Different GC Flavors
*GC Performance Counters