The timing settings have just as big an impact on RAM performance as the bus frequency. After all, the data bus can only capitalize on the vast bandwidth if data is read out of the RAM chips and made available at a fast enough clip. And when the data is accessed from different memory zones, there are a whole slew of processes that stop up the flow of data. The memory timings define the speed with which all the individual steps involved in accessing RAM are done. It's more than worth your while to go to the trouble of optimizing these settings: your performance could increase by up to ten percent. What's more, optimizing your timing parameters can be more advantageous than increasing your bus clock. High-quality DDR333 RAM with quick timings will outperform a DDR400 module with timing settings that have been deliberately rolled back to increase the clock speed.
When tweaking your memory, the first step is to deactivate the automatic RAM configuration. When this function is activated, the mainboard reads the SPD chip (Serial Presence Detect) on the memory module to obtain information about the timings and clock speed and to adjust the settings accordingly. However, these settings, which the RAM manufacturer stores in the EEPROM chip, are very conservative in order to ensure stable operation on as many systems as possible. With a manual configuration, you can customize your settings for your own system - in most cases, the RAM modules will remain stable even when they exceed the manufacturer's specifications.
Nor should you gloss over checking your timing settings if you have inexpensive memory modules. Generic providers are famous for cutting corners during production and burning the wrong values into the SPD chips. Unhappy buyers are forced to struggle with poor performance or system crashes without knowing exactly why.