Why there is RAM latency?

[avvia]

hi,
Overclocking to CPU and fine tuning the bios are some the most common ways to optimize system. Another often overlooked method is reducing the RAM’s latency.Why the RAM has a certain latency to start delievering data?Any recommendations and suggestions are appreciated.

[Baltazar]

RAM latency occurs when the CPU needs to retrieve information from memory. In order to receive information from RAM, the CPU sends out a request through the front side bus (FSB.) However, the CPU operates faster than the memory, so it must wait while the proper segment of memory is located and read, before the data can be sent back.

RAM latency is measured in wasted FSB clock cycles, since the data is transferred through the FSB. The bigger the latency number, the more FSB clock cycles it missed. The goal in reducing latency is to get the data back to the CPU in the least amount of FSB clock cycles possible.

[SecRecy]

hi,
The CAS Latency of your RAM is basically the amount of time your RAM sits ‘waiting’ for an instruction from the processor, and has an impact on overall system performance. Imagine a pair of identical high powered racing cars, sitting at the start line. If the driver of one has a longer reaction time to get the accelerator pedal pressed down, that car is going to be second to the finish line! A difference in your RAM’s CAS latency has a similar effect, and there are a hell of a lot of ‘Stop/starts’ involved in the way your computer functions!

[Joshua]

In general, the period of time that one component in a system is spinning its wheels waiting for another component. Latency, therefore, is wasted time. For example, in accessing data on a disk, latency is defined as the time it takes to position the proper sector under the read/write head.

In networking, the amount of time it takes a packet to travel from source to destination. Together, latency and bandwidth define the speed and capacity of a network.

In VoIP terminology, latency refers to a delay in packet delivery. VoIP latency is a service issue that is usually based on physical distance, hops, or voice to data conversion.

[Russell]

RAM latency refers simply to the ammount of clock cycles your RAM waits to do a particular task. with SDRAM (synchronous dynamic random access memory, not to be confised with the terms sdr or ddr which are both types of SDRAM) timming is everything, as the name "Synchronous" implies. because the RAM is dynamic, and not static (flash memory is a static memory) it requires constant "refreshing" of the data bits it has stored in its banks, refrsh "shots" of voltage going through it at a certain rate. obviously, the more often this refresh occurs, the less likely the RAM is to lose any data bits. the setting for refresh timmings add to latency.