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Does RAM speed matter?

RAM is one of the primary components in a PC, and it’s important that you have at least a certain amount of RAM depending on what you want to do with your PC. However, there are more things to RAM than just capacity: Frequency and latency are important considerations, too.

The question of whether RAM speed matters is especially important now, as Intel’s 12th-generation Alder Lake CPUs launched in late 2021 and can use both DDR4 and DDR5 RAM. The official maximum clock speed for DDR4 was 3200MHz, while DDR5 starts at 4800MHz, an increase of 50%. Although latency significantly went up, from CL14 on most 3200MHz DDR4 kits to CL40 on most 4800MHz DDR5 kits, DDR5 is still supposed to be faster.

So, does RAM speed matter? The short answer is: It depends.

What makes RAM fast?

Corsair DDR5 RAM inside a PC.

RAM speed is effected by three key things: Higher frequencies, lower latencies, and more channels. Each of these aspects is distinct and means different things for the performance of RAM.

Frequency or clock speed is the most straightforward thing: You increase it, and the performance goes up. Increasing frequency increases memory bandwidth, or the amount of data that can be transferred at any given time. It’s pretty simple, and overclocking RAM works basically the same way as overclocking your CPU or GPU.

Latency is the other side of the coin, because lower latency doesn’t increase the amount of data transferred per second, but it does decrease the amount of time needed for the CPU and RAM to communicate. Manually lowering latency is much more complicated and difficult than increasing frequency, so it’s almost certainly not worth the hassle for most users. We recommend you merely enable XMP, which will set your RAM to the highest frequency and lowest latency that your RAM is rated for.

One more thing to note about frequency and latency: Improving one often comes at the expense of the other. It’s harder to increase frequency while increasing latency, and vice versa. This is another reason that, if you want to overclock, increasing frequency alone is generally better than increasing frequency and latency together.

Memory channels aren’t something you can change in a settings menu, but rather, they depend on your CPU and how many sticks of RAM you have. Mainstream motherboards and processors typically only offer two memory channels. If you have two or four sticks of RAM, they will run in dual-channel mode. If you have just a single stick, your RAM will run in single-channel mode, which incurs a critical memory bandwidth penalty.

How does faster RAM improve the performance of my PC?

It’s all about the CPU, which needs access to lots of data that can be quickly transferrable. CPUs actually have their own exclusive high-speed memory called cache, but cache is only available in small quantities (even the Ryzen 7 5800X3D only has 96 MB of shared cache). The CPU will inevitably ask the RAM for some data, and when that happens, the RAM becomes the bottleneck, so in theory, faster RAM means better performance.

But in practice, not all software is the same, and not all applications and games depend on RAM in the same ways, much like how not all applications and games benefit from more CPU cores, faster individual cores, or faster graphics. Your experience with faster RAM is going to depend on what you do with your PC.

Performance benchmarks

Intel Alder Lake box with DDR5 memory.
Image used with permission by copyright holder

So, exactly how much performance do you stand to gain by going from single- to dual-channel memory, increasing frequency, or lowering latency? It’s difficult to answer this comprehensively, so we’re just going to focus on mainstream applications and games.

Unfortunately, not very many people or publications compare single-channel memory to dual, mostly because everyone just uses two sticks of RAM unquestioningly. However, for laptops, this is actually very important, because many laptops by default run in single-channel memory (which is terrible) or have half the memory soldered to the board and the other half in a RAM slot. The Asus Zephyrus G14 belongs in the latter category, and Ultrabook Review did some testing on it to see how bad single-channel memory was.

Switching from dual- to single-channel memory impacted the performance of most applications, from synthetic benchmarks to games. The gaming benchmarks are particularly interesting because you would expect the G14’s 2060 Max-Q to be the most limiting factor. Yet performance drops by nearly 20% in Shadow of the Tomb Raider. If this was a test using a much faster laptop or a desktop that could run games at a higher framerate, you’d see a much larger difference between the single- and dual-channel memory benchmarks.

In benchmarks focusing specifically on frequency and latency on both DDR4 and DDR5 memory, Techspot tested a variety of applications and games on Intel’s 12th-gen Alder Lake CPUs. The TL;DR here is that the frequency and latency usually doesn’t matter much. In Adobe Photoshop 2022, there were noticeable performance differences between slower and faster RAM, though these differences were modest. In most games, the fastest 6200MHz DDR5 memory wasn’t noticeably faster than even the slowest 2400MHz DDR4. Cyberpunk 2077 and Hitman 3 did, however, show the 6200MHz RAM achieving 29% and 15% more frames, respectively.

Although faster RAM doesn’t always mean better performance, it is still a good idea to get a decently fast kit of RAM. At the time of writing, there’s almost no price difference whatsoever between a 16GB kit of DDR4 2400MHz RAM and a 16GB kit of DDR4 3600MHz RAM, so paying a few bucks more for the 3600 MHz is totally worth it.

As for DDR5 memory, well, it’s nearly twice the price of DDR4, and at least on Alder Lake, you’re not getting your money’s worth. Maybe DDR5 will be worth it for Ryzen 7000 and Raptor Lake, but Alder Lake users should be just fine with DDR4, unless you’re targeting absolute peak performance regardless of budget.

Of all the things that impact memory performance, dual-channel mode is easily the most important. Not only is it easy to enable (you just need to have two or four sticks of RAM), but it also greatly increases performance in both applications and games. Meanwhile, frequency and latency are important sometimes but usually don’t matter very much, if at all.

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Matthew Connatser
Matthew Connatser is a freelance writer who works on writing and updating PC guides at Digital Trends. He first got into PCs…
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