Is your RAM getting slower and slower?

One of the most repeated statements among the “experts” of the network is none other than that DDR5 memory is much slower than DDR4. His argument? The latency numbers in the specs are much higher . But, are they correctly interpreted by them or, on the contrary, are we dealing with a myth that has been taken for granted? Let’s see.

When choosing memory we usually look at the detail of the bandwidth and the capacity that it brings, however, there is a crucial element that can make the difference, or not, in performance between choosing one memory model or another . That is why we are going to explain why DDR5 is not always slower than DDR4.

Is your RAM getting slower and slower

How to understand RAM latency

We understand by memory latency the time in which a processor takes to establish a contact to start the data transfer between both parties. This process occurs when the address of the memory that needs to be accessed is changed, but not for the sequential transfer rate. So RAM latency is something that affects performance more the more jumps are being made from one part of memory to another.

The formula used to calculate RAM latency is as follows: CL *2000 /DR where:

  • CL is the CAS Latency that the technical specifications of the RAM memory say. In the case of standard DDR4 it is usually 22, while in DDR5 it is 40. However, depending on the transfer speed and the manufacturer, this figure may vary.
  • DR is Data Trasfer and it is the transfer speed per pin, in the case of the DDR4-3200 it will be 3200 and in the case of the DDR5-4800 the figure is 4800.

RAM CPU Latencia

DDR5 vs. DDR4 on latency

Once we have made the pertinent explanation of how latency works, we must start from the fact that as time passes and new RAM modules appear, it is normal for the access time to shorten, even among those of the same speed. access and type. For example, among the DDR4-3200 memory modules we can find models with a CL of 22 and in which the CPU takes 13.75 nanoseconds to access, but there are also those with a CL of 16 that take no more than 10 nanoseconds.

Memoria RAM 8 16 32 GB

In the case of DDR5 we have seen DDR5-4800 memory with a latency of 40, which gives 16.67 ns of access time, but a year later we have DDR5-5200 modules with a CL of 38 and an access latency of 14 .62 nanoseconds. So it is not that DDR5 has more latency than DDR4 and that’s it, but we have to take into account the factors that influence it.

The good news is that high-speed DDR5 memory such as the G.Skill Trident Z5 and Corsair Vengence DDR5 are DDR5-6000 and have a CL of 36 . Which puts them at 12 nanoseconds, a much lower latency than existing standard DDR4 on the market.