If you would like to know more about speed vs latency, check out this in-depth article. In most cases you shouldn't worry about your memory timings. If you have any further questions be sure to reach out to Crucial support. All rights reserved. Neither Crucial nor Micron Technology, Inc.
All other trademarks and service marks are the property of their respective owners. Find a product Part no. Your search did not match any active Crucial part numbers or configuration IDs.
Find articles and site content Enter keywords. What are memory timings? Refresh : refreshes the charge in memory cells by writing data back in place without changing it.
All banks must be idle precharged before a refresh. Timings are generally divided into three categories: Primary, Secondary, and Tertiary. Primary is the broadest, the rated settings are listed on the box e. Secondary are non-primary timings that can optionally be set in SPD see next section.
Their names and definitions will be covered in a future article. That last paragraph requires some additional explanation. They are responsible for standardizing and defining everything in this article, from abbreviations to the entire concept of DDR4.
When a newly-built system is powered on for the first time, the board will check SPD and default to the best set of these JEDEC approved slow-but-safe speeds. Even if memory manufacturers wanted to go deeper, there is a specific and limited list of SPD entries. Enabling XMP and calling it a day generally does a good enough job. XMP will cover that camp. This is one area where board manufacturers can secure an advantage in performance, because the sheer variety of RAM and the differences between Samsung, Micron, and Hynix chips make tertiary timings hideously complex to adjust.
Memory and board manufacturers can work together to bake-in optimal timings for popular kits, but for the most part these are determined if left on auto during POST, where they should remain unchanged unless there are boot failures.
On the user end, it can feel like trying to solve a jigsaw puzzle by shaking the box, but it works. SKILL kit in tests. When we adjusted the G. This is an extreme case, but it shows both the value of experimenting with subtimings and the frustrations of benchmarking memory. This is the number of cycles it takes to read the first bit of memory from a DRAM with the correct row already open.
Unlike the other numbers, this is not a maximum, but an exact number that must be agreed on between the memory controller and the memory. The first classification, DDRxxx, is the standard used to classify memory chips, while the second classification, PCyyyy, is the standard used to classify memory modules. Pay attention to the RAM timings and voltage 1. If the memory module is installed on a system where the memory bus is running at a lower clock rate, the maximum transfer rate the memory module will achieve will be lower than its theoretical maximum transfer rate.
Actually, this is a very common misjudgment. This is the maximum clock rate they support, not the clock rate at which they will be running. So, why would someone buy these modules? Someone would buy them for overclocking. Since the manufacturer guarantees that these modules will run up to 2, MHz, you know that you can raise the memory bus clock up to 1, MHz to achieve a higher performance with your system. However, your motherboard must support this kind of overclocking read our tutorial on memory overclocking for more details.
Thus buying a memory module with a labeled clock rate higher than what your system supports is useless if you are not going to overclock your system. For the advanced user, there is yet another characteristic: the temporization of the memory, a.
Because of timings, two memory modules with the same theoretical maximum transfer rate can achieve different performance levels. Why is this possible if both are running at the same clock rate?
Timings measure the time the memory chip delays doing something internally. Here is an example. A memory module with a CL 9 will delay nine clock cycles to deliver a requested data, whereas a memory module with a CL 7 will delay seven clock cycles to deliver it.
While both modules may run at the same clock rate, the second one will be faster, as it will deliver data sooner than the first one. The memory timings are given through a series of numbers; for instance, , , , or These numbers indicate the amount of clock cycles that it takes the memory to perform a certain operation. The smaller the number, the faster the memory. The memory module portrayed in Figure 1 has timings, while the memory module portrayed in Figure 2 has timings.
To understand them, bear in mind that the memory is internally organized as a matrix, where the data are stored at the intersection of the lines and columns.
0コメント