RAM is often shipped from the factory at a slower speed than silicon is capable of. With a few minutes in the BIOS and a little testing, you can get your memory to run faster than what the manufacturer claims.
What you need to know before you start
RAM is a bit trickier than CPU or GPU overclocking, where you just turn the dial and pray your fancy all-in-one water cooler doesn’t turn your system into a heater. You can turn a lot of knobs with RAM, but it’s also much safer because they don’t generate much heat.
This has real benefits. Every program you use saves its working data in RAM before being loaded into the CPU’s internal cache, and programs that use it in large quantities can move around RAM like butter. In games, improving the overall latency of your RAM can significantly reduce frame times. This can improve overall frame rates and (most importantly) reduce stuttering in CPU intensive areas where new data needs to be loaded from RAM to cache or VRAM.
The speed of RAM is usually measured in megahertz (MHz). The standard DDR4 speed is usually 2133MHz or 2400MHz, although the actual speed is actually half as much as it is double data rate (DDR). On top of that, your memory has over twenty different timings that control latency and read and write speed. They are measured in units of clock cycles and are often grouped under the acronym «CAS Latency (CL)». For example, a midrange DDR4 kit might be rated at 3200MHz CL16. Improving speed or timing improves latency and throughput.
The memory communicates with the rest of the computer using a system called Serial Presence Detect. Because of this, it gives the BIOS a set of frequencies and primary timings at which it can operate, called the JEDEC specification. This is the standard speed, and it’s baked into every DDR4 flash drive ever made.
But Intel found a way to trick the system. By offering another profile on top of JEDEC called XMP (Extreme Memory Profile), they can handle RAM above standard speeds. If you buy RAM over 2400MHz, you will most likely get a kit with an XMP profile that can be enabled. It’s sanctioned, factory overclocked.
But here’s the thing — due to several factors, this overclock is usually not the best, and you can push it further than the manufacturer intended.
For one thing, manufacturers don’t bin everything 100%. They have to price more expensive kits, so it’s often the case that your memory came with an XMP profile, which was due to product segmentation. Your kit also operates at a certain voltage level, typically 1.350V for mid-range DDR4, but you can increase this a bit yourself, which is what manufacturers do for higher speed kits.
But the main problem is that the SPD does not reveal every moment of time. According to a rep in Kingston, they «tune only the ‘primary’ timings (CL, RCD, RP, RAS)» 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 what not always makes the right choice. In my case, my ASUS motherboard’s «auto» settings set some weird values for some timings. My RAM kit refused to work with the XMP profile out of the box until I set the time myself.
How to determine the ideal RAM time
While overclocking RAM is pretty safe, it’s also a bit more complicated than just spinning up a drive. If you are using an AMD Ryzen system, you are in luck as there is a tool called «Ryzen DRAM Calculator» that makes this whole process easier. The calculator will save you some trial and error and you won’t need to leave your RAM in the motherboard’s «AUTO» settings.
For Intel systems, this tool is still handy as a guide to primary timings, and the built-in memory tester will work the same way. You’ll want to download this too, even if you’re not using an AMD system.
Open the tool and specify which version of Ryzen you’re running (just install Ryzen 2 Gen if you’re using Intel) and what type of memory you have. If you don’t know, you can find it online by searching Google for your RAM kit’s part number.
Click the purple «R — XMP» button at the bottom to load your kit’s XMP profile. Enter in your Ryzen version and memory type and click «Calculate SAFE» to calculate the time. You can use the «Compare Times» button to view a comparison with your XMP settings. You will find that many deadlines are tightened.
SAFE settings will almost always work; I had no problems with them at several frequencies at stock voltage. FAST time will probably work but may not be stable at supply voltage
To take advantage of this, you need to save a screenshot (there is a button in the lower left corner) and send it to a separate device so that you can view it in the BIOS.
How to overclock your RAM in BIOS
Make sure you have 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 the computer and boot it back to the BIOS or UEFI firmware setup screen. You often have to press a key such as «Del» when booting up your PC to access this screen. You will be presented with a screen similar to this one:
Locate the memory section and upload your XMP profile to get started. Make sure the frequency is what you want. If you don’t even want to touch the timings, you can increase the frequency while keeping the same timings (especially on Intel platforms).
There should be another section for time control. Open it:
Now open the screenshot on your phone and start entering numbers. In my case, the order matched the calculator, but you need to double-check and check everything.
In my case, the ASUS BIOS displayed the full names for many of the primary timings, so here is a list of the primary timings and their associated jargon:
tCL — main tCL CAS
tRCDRD — read delay from RAS to CAS
tRCDWR — Write delay from RAS to CAS. It is sometimes grouped with the read, although not always.
tRP — RAS Precharge (PRE) Time
tRAS — RAS Active (ACT) Time
The rest must match exactly.
For Intel, you’ll at least want to enter the primary timings, and you can leave the rest on auto. If you want, you can try entering the subtypes that the calculator gives. I don’t see any reason why this shouldn’t work, but I can’t test on my Ryzen system. If you have problems with automatic settings, try entering them manually.
Once you’re done with the timings, find the voltage control section. You can enter the recommended DRAM voltage (the calculator displays potentially unsafe voltages in red. Anything below 1.450V will probably work). If you’re on Ryzen, you’ll need to enter the recommended SOC voltage that powers the memory controller on the processor.
Save the settings and exit the BIOS (on my computer I have to press F10 to do this). Your computer should restart, and if it boots into Windows, you can proceed to the next step.
What if it’s not a POST
If it doesn’t boot, your motherboard most likely failed the power-on test (POST), you will probably have to wait about thirty seconds for the BIOS to boot into safe mode and restore the last working settings. You can try increasing the memory voltage in 25 millivolt (0.025 V) steps before reaching the maximum recommended voltage. You can also try raising the SOC voltage slightly on Ryzen systems, as Ryzen 1st and 2nd Gen are particularly finicky with memory overclocking. Intel does not have the same SOC as Ryzen, and most likely this problem will not occur.
If your computer won’t boot into safe mode, don’t worry, you haven’t turned it into a paperweight. Your BIOS probably doesn’t have this feature and you need to clear the CMOS manually. This is usually either the battery on the motherboard, which you can remove and reinstall, or a pin behind the connectors on the front panel. Please refer to your motherboard manual. You need to take a screwdriver or scissors (ideally, they make jumpers and switches for this, but most likely you don’t have them) and touch the two pins together, creating an electrical connection. Do not worry; it doesn’t shock you. The PC will return to normal.
Make sure overclocking is stable
Once you get back to Windows, the fun isn’t over yet. You want to make sure the overclock is stable. The calculator has a tab called «MEMbench» that you can use to do this. Set the mode to «custom» and the task scope to 400%. Click «Max. RAM» at the bottom to allocate any remaining RAM. This will check your RAM for errors four times.
Click «Run» when you’re ready to start and give it a few minutes. In my case, testing 32 GB of RAM at a task size of 400% took less than ten minutes.
If there are no errors, you can try to push the clock further or check the «FAST» settings. This is all memory overclocking is; only by trial and error, removing spam and waiting for MEMbench to complete. Some people find this type of routine soothing.
After you’ve exhausted your Numpad and are happy with your results, you’ll want to do a nightly test to make sure your overclock is completely stable. Set the scope of the task to something crazy (100,000% should do) and return to it as soon as you wake up. If there are no errors, you can enjoy overclocking. The worst thing that can happen if you skip this nightly step is that you might get a blue image or a random crash sometime down the line (which happens from time to time at any RAM speed if you don’t have ECC memory).
Rate your RAM to test performance
If you’re particularly competitive and want to see how your RAM compares to the competition, you can download UserBenchmark to compare your entire PC, including your RAM. This will give you a general idea of how well your system is performing. You can also use a game-specific benchmark such as Unigine Superposition , although you will most likely need to run multiple benchmarks as the margin of error for such benchmarks is quite high.
My results were especially impressive; I bought a 32GB Micron E-die kit (known to be cheap and well overclocked) priced at 3200 at CL16 for $130. UserBenchmark gave it a headroom score of 90% over average RAM, but even dropping the time to 3200 at CL14 gives it a 113% headroom, a 23% increase in performance.
This puts the $130 electronic micron kit on par with the 3200 @ CL14, which sell for over $250, which is quite a savings. These were just my results and your mileage will depend on how well your memory overclocks and how your CPU handles it.