A: No. An SDRAM DIMM with -10 (100 MHz) components is designated as a 66 MHz module. This type of module is not guaranteed to run consistently in a PC100, 100 MHz system. In order for the module to be PC100 compatible the components need to be marked with -8A, -8B, -8C, -8D or -8E (125 MHz). Modules with -8A through -8C components will run at 100 MHz at a CAS latency of 3. Modules with -8D or -8E components will run at 100 MHz at a CAS latency of 2.

A: Yes. The AC timing specifications on a PC133 device are tested to allow a system bus to run at 133 MHz. The PC100 and PC66 timing specifications are more relaxed on these timings. All Micron PC133 devices should work at PC100 and PC66. In fact, a -75 device is specified for PC100 timings using CAS latency = 2. Please refer to the AC timing table in the appropriate data sheet ^tCK at CL = 2.

A: The first number of the 2-2-2 designation refers to CAS latency, so in short you are asking the advantage of a CAS latency of 2 over one of 3. Adjusting a device to CL = 2 from CL = 3 will speed up access time from a READ command to the point at which data is available on the data bus (1 clock quicker). In recent testing, from Micron has found the following benchmark performance improvements in the 2-2-2 setting over the 3-2-2: