RAM often comes from the factory with a lower speed than the silicon is capable of. With a few minutes in your BIOS and a bit of testing, you can get your memory to run faster than the manufacturer’s specifications.
What You Need to Know Before You Begin
RAM is quite a bit more complex than CPU or GPU overclocking, where you’re merely cranking a dial and praying your fancy all-in-one watercooler doesn’t turn your system into a space heater. With RAM, there are many knobs to turn, but it’s also much safer because they don’t produce much heat.
This does have real-world benefits. Every program you use stores its working data in RAM before loading it into the CPU’s internal cache, and programs that use a lot of it can churn through RAM like butter. In games, improvements in your RAM’s overall latency can cut down on frame times significantly. This can improve overall frame rates and (most importantly) reduce stuttering during CPU-intensive areas, where new data needs to be loaded from RAM into cache or VRAM.
RAM speed is usually measured in megahertz (Mhz). DDR4 stock speed is usually 2133 Mhz or 2400 Mhz, though the real speed is actually half of that since it’s Double Data Rate (DDR). On top of this, your memory has over twenty different timings which control latency, and how fast you can read and write. These are measured in terms of clock cycles and often grouped up under the “CAS Latency (CL)” abbreviation. For example, a midrange kit of DDR4 may be rated at 3200 Mhz CL16. Improving either the speed or timings improves latency and throughput.
The memory talks to the rest of the computer using a system called Serial Presence Detect. Through this, it gives the BIOS a set of frequencies and primary timings that it can operate at, called the JEDEC specification. This is the stock speed, and it’s baked into every DDR4 stick ever made.
But, Intel found a way to cheat the system. By offering another profile on top of JEDEC, called XMP (Extreme Memory Profile), they could run RAM higher than the standard speeds. If you buy RAM that’s rated over 2400 Mhz, you’re likely getting a kit with an XMP profile you can enable. This is sanctioned, factory overclocking.
Here’s the thing though—due to several factors, that overclock usually isn’t the best, and you can push it further than the manufacturer intended.
For one, manufacturers don’t bin everything to 100%. They’ve got to price the expensive kits higher, so it’s often the case that your memory came with the XMP profile it did because of product segmentation. Your kit also operates within a certain voltage level, usually 1.350 volts for midrange DDR4, but you can turn this up a bit yourself, something manufacturers do for higher speed kits.
But the main problem is that SPD doesn’t expose every timing. According to a representative at Kingston, they “tune the ‘Primary’ timings (CL, RCD, RP, RAS) only,” and since the SPD system used to store XMP profiles has a limited set of entries, the rest is up to the motherboard to decide, which doesn’t always make the right choice. In my case, my ASUS motherboard’s “auto” settings set some strange values for some of the timings. My kit of RAM refused to run with the XMP profile out of the box until I fixed the timings myself.
How to Determine the Perfect RAM Timings
Although overclocking RAM is quite safe, it’s also a bit more complicated than merely cranking up the dial. If you’re running an AMD Ryzen system, you’re in luck, as there’s a tool called “Ryzen DRAM Calculator” that makes this whole process way easier. The calculator will take away some of the headaches of trial and error, and you won’t have to leave the RAM on your motherboard’s “AUTO” settings.
For Intel systems, this tool is still handy as a guideline for the primary timings, and the built-in memory tester will work the same way as well. You’ll want to download this too even if you’re not on an AMD system.
Open up the tool and enter in which version of Ryzen you’re on (just put in Ryzen 2 Gen if you’re on Intel) and what type of memory you have. If you don’t know, you can find it online with a Google search for your RAM kit’s part number.
Press the purple “R – XMP” button at the bottom to load your kit’s XMP profile. Enter in your Ryzen version and memory type, and press “Calculate SAFE” to calculate your timings. You can use the “Compare Timings” button to view a comparison to your XMP settings. You’ll find that many of the timings are tightened up.
The SAFE settings will almost always work; I’ve had no issues with them at multiple frequencies at stock voltage. The FAST timings will likely work, but may not be stable at stock voltage.
To make use of this, you’ll want to save a screenshot (there’s a button on the bottom left) and send it to a separate device so you can view it while in the BIOS.
How to Overclock Your RAM in Your BIOS
Make sure you’ve got a screenshot of the calculator saved on a separate device (or written down somewhere), because the rest of the steps will be in the BIOS, without access to your desktop.
Turn off your PC and boot it back up into its BIOS or UEFI firmware setup screen. You’ll often have to press a key like “Del” repeatedly as the PC boots to access this screen. You’ll be presented with a screen similar to this one:
Find the section for memory, and load your XMP profile to start with. Make sure the frequency is what you want. If you don’t even want to touch the timings, you can likely increase the frequency while keeping the same timings (especially on Intel platforms).
There should be another section for timing control. Open this up:
Now open up the screenshot on your phone, and start entering in numbers. In my case, the order matched up with the calculator, but you’ll want to double-check and verify everything.
In my case, the ASUS BIOS displayed the full names for many of the primary timings, so here’s a list of the primary timings and their associated jargon:
tCL– Primary CAS Latency
tRCDRD– RAS to CAS Read Delay
tRCDWR– RAS to CAS Write Delay. This is sometimes grouped with read, though not always.
tRP– RAS Precharge (PRE) Time
tRAS– RAS Active (ACT) Time
The rest should match up exactly.
For Intel, you’ll want to enter the primary timings at least, and the rest you can leave on auto. If you’d like, you can try entering the subtimings the calculator gives. I see no reason why this shouldn’t work, but can’t verify on my Ryzen system. If you have issues with automatic settings, try entering them in manually.
Once you’re done with the timings, find the section for voltage control. You’ll want to enter in the recommended DRAM voltage (the calculator displays potentially unsafe voltages in red. Anything below 1.450v is likely fine). If you’re on Ryzen, you’ll want to enter in the recommended SOC voltage, which powers the memory controller on the CPU.
Save the settings and exit the BIOS (on my PC, I have to press F10 for that). Your computer should restart, and if it boots into Windows, you can move on to the next step.
What to Do If It Doesn’t POST
If it doesn’t boot, your motherboard likely failed its power-on-self-test (POST) you’ll probably have to wait about thirty seconds for the BIOS to boot into safe mode and restore the last working settings. You can try bumping up the memory voltage in 25 millivolt (0.025v) increments before reaching the max recommended voltage. You can also try raising the SOC voltage slightly on Ryzen systems, as 1st and 2nd gen Ryzen are particularly finicky with memory overclocking. Intel doesn’t have the same SOC as Ryzen does, and will likely not have this issue anyway.
If your computer doesn’t boot into safe mode, don’t worry, you didn’t turn it into a paperweight. Your BIOS likely doesn’t have that feature, and you’ll need to clear CMOS manually. This is usually either a battery on the motherboard you can remove and reseat or a pin by the front panel headers. Consult your motherboard manual. You’ll need to take a screwdriver or a pair of scissors (ideally, they make jumpers and switches for this, but you likely don’t have those lying around) and touch the two pins together, creating an electrical connection. Don’t worry; it won’t shock you. The PC will reset back to normal.
Make Sure the Overclock is Stable
Once you’re back into Windows, the fun doesn’t stop yet. You’ll want to verify that the overclock is stable. The calculator has a tab called “MEMbench” that can be used for this. Set the mode to “custom” and the task scope to 400%. Click “Max RAM” at the bottom to allocate all of your remaining RAM. This will test your RAM for errors four times over.
Click “Run” when you’re ready to start and give it a few minutes. In my case, testing 32 GB of RAM at 400% task scope took less than ten minutes.
If there are no errors, you can try to push the clocks further, or test out the “FAST” settings. This is all memory overclocking is; just trial and error, spamming delete, and waiting for MEMbench to finish. Some people find this kind of routine soothing.
Once you’ve worn out your Numpad and are satisfied with your results, you’ll want to do an overnight test to verify that your overclock is absolutely 100% stable. Set the task scope to something crazy high (100,000% should do) and come back to it once you wake up. If there are no errors, you can enjoy your overclock. The worst that happens if you skip this overnight step is that you may receive a bluescreen or random crash sometime down the line (which does happen with any speed of RAM from time to time, unless you have ECC memory).
Benchmark Your RAM to Verify Your Performance
If you’re particularly competitive and want to see how your RAM stacks up against the competition, you can download UserBenchmark to benchmark your whole PC, including your RAM. This will give you an overview telling you how well your system is performing. You can also use a game-specific benchmark like Unigine Superposition, though you’ll likely have to run multiple tests as the margin of error is quite high with benchmarks like these.
My results were particularly impressive; I bought a 32 GB kit of Micron E-die (known for being cheap and good at overclocking) rated at 3200@CL16, for $130. UserBenchmark gave it a stock score of 90% speed compared to average RAM, but even tightening the timings to 3200@CL14 gives it a 113% score, a 23% performance increase.
This puts the $130 Micron E-die kit on par with 3200@CL14 kits that sell for over $250, which is quite the cost savings. These were simply my results, and your mileage will vary based on how well your memory overclocks and how your CPU handles it.