RAM manufacturers are pushing DDR4 RAM speeds ever higher. But there’s conflicting information about what RAM speeds can really do for you. In reality, there are four main factors in how RAM affects your system performance: capacity, number of channels, speed, and timings.
Tip: RAM or Random-Access Memory, is a type of fast memory that is used to store the data of programs that are currently running. RAM is a lot faster than HDDs or even SSDs, but it can only store data while your PC is still powered on.
For any system to run you need RAM, the absolute minimum amount of RAM required for Windows 10 is 2GB. It’s highly recommended that you get more than that though, as you will have a very bad experience. 8GB of RAM should be considered the basic amount but 16GB is recommended. With 16GB of RAM, you never have to worry about running out when playing games and having a few chrome tabs open.
Tip: GB, or gigabyte, is a standard unit of measurement for storage capacity. 1 gigabyte is one billion bytes.
Having too little RAM will slow your computer down, but with a minimum of 8GB of RAM, you should have enough for most situations.
Number of channels
RAM can run in single-, dual-, triple-, or quad-channel modes, although you’ll need to match the number of channels to the number of sticks of RAM. Theoretically, quad-channel RAM should have double the bandwidth of dual-channel RAM, however, in the real world, you’ll find minimal performance difference between dual- and quad-channel memory.
If your CPU and Motherboard both support only dual-channel you should only purchase dual-channel RAM, such as two 4 GB or 8 GB sticks of RAM as this is the optimal configuration. If your CPU and motherboard support quad-channel RAM, however, you can be a bit more flexible. Two sticks of RAM will only run in dual channel mode, halving your theoretical bandwidth, but assuming you would have purchased the same total capacity, you have more RAM slots free for potential future upgrades.
Tip: You should never mix RAM speeds. If you upgrade your RAM at a later date, it is recommended that you either entirely replace your RAM or purchase another identical kit. Installing mismatched RAM can cause system instability and will force the faster RAM to run at the slower speeds.
RAM speed is measured in MHz, or megahertz, which means millions of cycles per second. The fastest JDEC standard DDR4 RAM speed is 2132MHz, everything that offers a speed above that is overclocked, with a feature called XMP. XMP, or extreme memory profile, allows a RAM manufacturer to specify faster speeds and timings for its RAM.
The fastest available RAM as of July 2020 is a 5000MHz 2x 8GB kit from Corsair. In benchmark tests, specifically aimed at testing RAM you’ll find that a 3000MHz RAM kit will perform with roughly 3/5ths the speed of the 5000MHz kit. In the real world, however, the performance difference will be much less noticeable. Faster RAM will help your applications load faster, but you will not see anything like a 66% performance boost. In terms of price to performance, the ideal is somewhere around 2800MHz to 3200MHz.
Tip: If you do purchase XMP RAM, make sure that you enable XMP in your BIOS. XMP is not enabled by default, if you don’t enable it, you won’t see the performance that you paid for.
Another factor in RAM speed is the timings, they are generally shown in the format 16-18-18-36. There are many different timing factors and decreasing any of them helps to increase your performance. The single most effective timing value to change though is CAS Latency or CL.
CAS stands for Column Address Strobe, CAS Latency refers to the exact number of cycles between the RAM being sent a column address and the response with the first bit of data. A lower value means lower latency, but this is also reliant on the clock speed of the RAM. In the real world, slightly faster RAM timings will make an almost imperceptible difference.
All in all RAM speed can provide an improvement to RAM specific benchmark tests, however, in real-world scenarios, you’re not likely to find much performance improvement, and could likely better spend the money on a faster CPU or GPU.