When you're building a PC and looking at RAM, there are lots of different speeds to choose from. I have 32GB of 3600MHz CL18 Corsair Vengeance DDR4 RAM, which is pretty decent when paired with an Intel Core i9-14900K. It's not the best RAM or anything out there, but it's good enough, especially for applications that are RAM-sensitive. When I was doing some routine maintenance on my PC, though, I noticed that I was running my RAM at a speed far, far lower than I should have.

Back when I built my PC in 2022, I had migrated my Windows install from my old PC on the same SSD that I transferred over, and when I had enabled XMP in the BIOS, my PC would blue screen. Everything else worked fine, so I disabled XMP with the expectation that I would come back to it in the future. I then forgot that I had disabled it, and only in the last couple of weeks did I make the realization that I had disabled it and never switched it back on. It had defaulted to 2133MHz, a far cry below what it should have been.

If you're on AMD, this setting might be called DOCP or EXPO. It's the same as XMP.

How to check if your RAM is set to the right speed

You can do it in task manager

Firstly, you'll want to check what RAM you have in your PC. If you aren't sure of the exact model number, you can easily check using the command prompt.

1. Open the Start menu on your PC and search for the Command Prompt.
2. Click Run as administrator.
3. Type wmic memorychip list full. This will bring up a full list of specs for the RAM in your PC, including things like memory type (such as DDR4 or DDR5).

Here, you'll see your model number. Google it, and you'll see what speed your RAM should be operating at. Next, open Task Manager, click Performance, and click Memory. Make sure your Speed matches what it should be. For example, my PC has 3600 MHz RAM, so it says that the speed is 3600 MT/s.

If it's not set to the right speed, then you'll need to set it in your BIOS!

How to set your RAM to the right speed

You'll be enabling XMP

Depending on the motherboard you're using, this setting may be in a different place.

• MSI: You'll find XMP on the OC menu under DRAM Setting, or it may be called A-XMP
• ASUS: Extreme Tweaker is what you want to look for, and a setting for AI Overclocking
• ASRock: Look for the OC Tweaker menu, which will have an entry for XMP or EXPO
• Gigabyte: Look for the Tweaker menu, which will have an entry for Extreme Memory Profile

When you first boot your PC, it will use default settings that will ensure a stable first boot. However, default JEDEC profiles for RAM are pretty conservative and can be beaten by the speeds that your motherboard or CPU may support. You're still technically overclocking your RAM, but in a way that the RAM is designed to support. You should also make sure to test your computer's stability once you enable it, which is why I had initially disabled XMP when I first built my PC and never came back around to fix it.

On top of that, if you're trying to run four modules of DDR5 on a modern motherboard, you might have to dial down the speeds from the XMP settings to get them to run reliably. Modern CPUs are better at supporting faster RAM when only two modules are installed, as four can put a bigger strain on the integrated memory controller.

Why your RAM speed matters

Apps and games can run better with faster RAM

First and foremost, your RAM speed matters because you should be getting what you paid for. If you paid for 3600 MHz DDR4 RAM, then you should be getting those speeds, rather than running at 2133MHz. That part is obvious, but the reasons are pretty important. You'll get significantly better CPU performance with faster RAM, as your RAM speed refers to the bandwidth of data that the RAM can transmit per second. As an example, my 1% lows have massively improved in Counter-Strike 2 since I re-enabled XMP.

As for why it's faster, it's a surprisingly simple answer. Running your RAM at a higher speed means that your CPU can access data faster, as a higher bandwidth means more data gets transmitted at once. Modern systems are also optimized for higher-speed RAM, and that's especially true for AMD's Ryzen CPUs, where the effect is even more pronounced. AMD CPUs use CCXs, and most high-end AMD CPUs have two CCXs that communicate via Infinity Fabric, an interconnect architecture that connects them both.

When you build a PC with Ryzen, you want to make sure your RAM speed is matched to your FCLK, as if they don't match, it can "decouple" which will massively increase latency. When a core in a CCX needs to get data from another core in the other CCX, it has to go through the Infinity Fabric connection, or when it needs to get data from RAM. Your BIOS will typically handle this for you once you set FCLK in the BIOS to auto, though you may need to manually tweak this if your RAM is too fast.

With faster RAM, you'll get better performance, and with faster RAM that matches your FCLK on Ryzen, you'll get the best performance possible out of your system. Without it, you're leaving performance on the table that you could massively benefit from.