As a PC builder, one of the most enduring questions I've encountered is how much RAM speed and timings matter. With many people transitioning from DDR4 to DDR5, I thought it would be a good time to revisit this question.
In general, faster RAM tends to show benefits when using applications where the CPU isn't the bottleneck. If the CPU's cores are working hard, it doesn't matter as much how fast data is moving from the RAM to the CPU. This means that tasks like video and image editing, AI, and file compression won't be affected too much by RAM speeds. However, there are exceptions for specific applications.
RAM speeds can make a difference for gamers, but it's important to note that the GPU is still the biggest hardware factor affecting gaming performance. Having a sufficient amount of RAM is more important than having faster RAM. However, if all things are equal, a good rule of thumb is that DDR5 6000 tends to be a good sweet spot between cheaper 4800 speed kits and pricier modules rated at 8,000 or higher.
AMD has come out and said that DDR5 6000 is a sweet spot for their Ryzen 7000 and 8000 series processors. Intel has not made a similar statement, but 6000 is also about right for their processors. Getting too far above 6,000 megatransfers can make it difficult for a memory controller to keep up with all that incoming data.
Chips with 3D cache do not benefit as much from higher DDR5 speeds because the extra cache memory helps make up for RAM that's slower than otherwise might be ideal. However, this doesn't mean you can't try to use RAM above 6,000 megatransfers. At that point, you're getting into the realm of possible instability or diminishing returns.
It's important to note that some of your luck will come down to the "Silicon Lottery." Some chips come off the assembly line with more overclocking potential than others. Not all games will benefit from faster RAM, and it tends to matter more when you have games that run at lower resolutions and higher frame rates.
When it comes to latency, lower numbers are better if you can afford them. However, it isn't likely that you'll see a big benefit from spending a lot more money just to get the lowest timings possible.
In summary, while RAM speed can make a difference for certain applications and tasks, it's important to keep in mind that other factors, like the CPU and GPU, play a bigger role in overall performance. As a first-person perspective, I recommend prioritizing a sufficient amount of RAM and investing in a good CPU and GPU for the best performance.