How much is trfc set?

TRFC value belongs to the second small parameter, indicating the refresh interval period, the unit is cycle, the smaller the value, the better.

DDR3 memory usually has a value of 90-120. Below 80, it may cause instability. CL, tRCD, tRP and tRAS are called the first timing, which have the most obvious and important impact on particle performance. (Recommended learning: phpstorm)

First of all, memory timings (English: Memory timings or RAM timings) are four parameters that describe the performance of synchronous dynamic random access memory (SDRAM): CL, TRCD, TRP and TRAS, the unit is clock cycle.

It is clear that in order for the computer to work in an orderly manner, there are strict requirements for the generation time, stabilization time, cancellation time and mutual relationship of various operation signals.

Exerting time control on operation signals is called timing control. Only strict timing control can ensure an organic computer system with various functional components.

Factors affecting memory timing:

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 (clock 1333 MHz, 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).

Note: Memory bandwidth is a measure of memory throughput and is typically limited by transfer rate rather than latency.

By interleaving access to multiple internal banks of SDRAM, it is possible to transfer continuously at peak rates. Increased bandwidth may come at the expense of increased latency.

Specifically, each new generation of DDR memory has a higher transfer rate, but the absolute latency does not change significantly, especially the first new generation products on the market, which usually have higher transfer rates than the previous generation. Long delay

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