The first 3 settings are the most important. 4-4-4 or 5-5-5 for example. The first setting is the most important, the CAS Latency. The lower the timings, the more responsive the RAM becomes. The higher the timings the less responsive or more flexible the RAM's function becomes. This holds true for all the timings you see in your BIOS, not just the first 4 (ex. 2-3-3-6). Just concentrate on the first 3 settings for practical purposes. Google again to get an explanation of exactly what each individual setting controls precisely.