Before we move to comparing if 2666MHz RAM is better than 2400MHz DDR4 RAM, lets understand what is meant by DDR4, 2666Mhz and 2400MHz in RAM or memory.
DD44 stands for “Double Data Rate 4th gen”. It is the 4th generation of Double Data Rate RAM with the preceding generation being DDR3 or DDR2. Since 2016, its commonly been used in personal computers (laptop and desktops).
What are the benefits of DDR4 over DDR3?
Few of the advantages of DDR4 RAM compared to DDR3 RAM are as follows:
- DDR4 has faster data transfer rates – maximum transfer rate of 3200 Mbps vs. 2666Mhz for DDR3
- DDR4 has much larger capacity – maximum capacity of 64 GB per module compared to 16 GB for DDR3
- You get better power savings with DDR4 because of lower voltage (1.2V compared to 1.5V for DDR3). This makes it a better RAM for on-the-go devices like Laptops, notebooks and mobiles
- DDR4 has higher chip densities of 4GB to 16GB compared to DDR3 chip densities of 512 MB to 8 GB.
What does MHz in RAM mean?
Also called as RAM speed, it denotes the maximum number of clock cycles per second that the RAM operates on. A RAM with speed of 2400 MHz performs 2.4 billion cycles per second or the amount of data transferred in a second.
Corsair has announced what it calls the world’s fastest DDR4 memory, which operates at a ludicrous speed of 4,600MHz.Courtesy: Techradar
The number of clock cycles per second the RAM can perform per second translate to how much data can be read and written.
Keep in mind that memory from a well-known company will always have better speeds than stated in specs due to several factors like adaptability to your specific motherboard.
My personal favorite brands are Kingston, Corsair, SK Hynix, samsung keeping in mind their product range, reputation & my budget.
This is just the first step in answering the question, is 2666MHz RAM better than 2400MHz. Don’t forget the untold secret of CAS latency.
Almost all laptop seller companies like Dell, HP, Lenovo would specify the Clock speed, DDR generation and size of RAM but not the secret CAS latency.Tweet
This is where the secret lies. Read further to understand.
Does RAM CAS latency matter?
RAM speed largely depends also on the CAS latency or the “CL” or “C” number mentioned on the RAM along with 2400mhz vs 2666mhz clock speed or Frequency. You can see CAS latency on RAM stickers either separately written or joined together with other numbers.
To find out whether RAM CAS latency matters for 2400mhz vs 2666mhz RAM, you can compare the CAS latency number and description for the following RAM chips.
- Kingston Technology HyperX Impact 16GB 2400MHz DDR4 CL14 260-Pin SODIMM Laptop Memory HX424S14IB/16 – this is a CL 14 CAS latency RAM
- Corsair 16GB Module (1x16GB) DDR4 2133MHz Unbuffered CL15 SODIMM – this is a CL 15 CAS latency RAM
Quick formula to calculate RAM speed for comparison
Following is a simple, easy to calculate formula to compare RAM based on speed:
X = clock speed / latency
Now go and buy the RAM with higher X-value. In the examples mentioned above, for Kingston RAM mentioned above, the X-value is 2400/14 while the X-value for Corsair RAM is 2133/15.
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The complete & exact formula to determine true latency in nanoseconds is:
Latency in nanoseconds = (CAS latency/RAM clock speed) x 2000
As per this formula if you want to find whether RAM CAS latency matters, keep in mind that the higher frequency RAM is better than RAM with higher CAS latency, if the X-factor is same in both RAMs.
For example, when you compare a DDR4 2400MHz RAM with a CAS Latency of 12 and a DDR4-3000MHz RAM with a CAS of 15, the X-factor for both will be 20. However due to higher frequency of 3000Mhz DDR4 RAM, I would suggest you buy the DDR4-3600 one.
The RAM with higher MHz speed is better out of 2 RAM chips if their CAS latency is same. Whereas, RAM with lower CAS latency is better if they have same MHz speed.Tweet
Note: I am not promoting either of the RAMs. I am not even proclaiming this as the perfect formula to evaluate your selection. This is just a quick formula to select from hundreds of RAMs when buying online.
Thank you for reading this article. I have written several other such Technology related articles in other sections on this website.
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