The difference between memory timing 1t and 2t

The difference between memory timing 1t and 2t:

1T has less delay and better system memory performance. But poor compatibility. Suitable for when your DIMM is not full.
2T has longer latency and much poorer system memory performance. High compatibility and stability. Suitable for when all your DIMMs are filled.

Extended information:

Memory timings (English: Memory timings or RAM timings) are four parameters that describe the performance of synchronous dynamic random access memory (SDRAM). Parameters: CL, TRCD, TRP and TRAS, the unit is clock cycle. They are usually written as four numbers separated by dashes, such as 7-8-8-24. The fourth parameter (RAS) is often omitted, and sometimes a fifth parameter is added: Command rate (command rate), usually 2T or 1T, also written as 2N, 1N. These parameters specify the latency (latency) that affects the speed of random access memory. Lower numbers generally mean faster performance. The final element that determines system performance is the actual latency, usually measured in nanoseconds.

When converting memory timing into actual latency, the most important thing to note is that it is in clock cycles. Without knowing the time of a clock cycle, it's impossible to know whether one set of numbers is faster than another set of numbers.

For example, the clock frequency of DDR3-2000 memory is 1000 MHz, and its clock period is 1 ns. Based on this 1 ns clock, CL=7 gives an absolute delay of 7 ns. The faster DDR3-2666 (1333 MHz clock, 0.75 ns per cycle) may use a larger CL=9, but the resulting absolute delay of 6.75 ns is shorter.

Modern DIMMs include a Serial Presence Detect (SPD) ROM chip that contains recommended memory timings for automatic configuration. The BIOS on the PC may allow the user to adjust timings to improve performance (at the risk of reducing stability), or in some cases increase stability (such as using recommended timings).

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