31. Read RAM Timings
The recommended values for the settings in Tips 27 through 30 appear most often on the memory module itself. A set of values that reads "2.5-4-4-8" is specified in clock cycles, and means the CAS Latency is 2.5 cycles, the RAS to CAS Delay is 4 cycles, the RAS Precharge Delay is 4 cycles, and the Active Precharge Delay is 8 cycles. These represent the setting values that the manufacturer recommends for the memory’s specified clock frequency. Smaller values may very well work, but they also risk system crashes. To improve performance, reduce these values incrementally one at a time, and test each change for system stability and performance, as shown in Screenshot L.
32. Increase RAM Input Voltage Levels
When RAM runs faster, it needs more voltage. That’s why you must boost input voltage levels to match clock rate increases.
The "DDR Reference Voltage" option permits voltage levels to be raised in increments of 0.1 volts. Increasing this value makes sense only when you’ve reduced one or more timing values or have increased the frequency of the memory clock, and when stability problems begin to manifest.
Warning : Setting input voltage levels too high can destroy memory modules in some cases !