What You Need to Know about RAM Speeds – Is Faster RAM Worth It?
For years now, PC enthusiasts have been obsessed with getting the fastest available hardware components for their shiny new builds. When it comes to RAM, though, this might not be the best way to go...
When buying RAM, you’ll see a large number followed by MHz (Megahertz). This, as you probably already know, represents the speed of the memory you're looking to purchase. But how does RAM speed affect your computer and the tasks it's trying to perform?
Is higher speed RAM good for gaming? Is higher MHz RAM better in general? And what’s the best RAM speed overall?
These are the sort of questions that gamers and keen PC builders ask themselves regularly and the very reason why we're going to try to explain what RAM speed does and whether it's worth the extra money.
Faster RAM speeds allow your processor to access the data stored in the hard drive quicker, giving your system a boost in processor performance.
What Is RAM?
How Does RAM Work?
Random Access Memory is an integrated circuit chip made from millions of transistors and capacitors. Each pair of transistor and capacitor make up a cell, and these cells are where the data is stored.
These cells hold and release electrical charges to write, rewrite, and erase data. This allows data to regularly change much faster than your traditional mechanical drive (HDD) that uses platters and actuator arms. Even SSD's can't compete with the speeds RAM provides.
RAM is also volatile, meaning that any data that is held within its cells will be lost when it loses power. This is why we don’t permanently write data to our RAM modules.
The Random Access part of Random Access Memory comes from the fact that data can be written to any cell in any order, and can be read from any cell as long as the physical location of the cell containing the data is known.
What Does RAM Speed Do?
So, what does RAM speed do? The speed of RAM is a tricky subject and one that actually comes down to several different factors, not just the MHz clock speed. To get a real sense of how fast our RAM is, we need to take into consideration the CAS latency and clock speed simultaneously.
Clock Cycles (RAM MHz)
RAM frequency works off of clock cycles (people often call this the RAM speed even though it is only part of the speed equation). Each read and write is done on a cycle. RAM is measured by how many cycles per second it can perform. For example, if RAM is rated at 3200 MHz, it performs 3.2 billion cycles per second.
The more cycles your RAM can perform per second translates to how much data can be stored and read - making for smoother user experiences. There's usually a direct correlation between higher DDR (Double Data Rate) RAM and the clock cycles those modules accommodate. This can easily be seen when comparing DDR3, DDR4, and now DDR5 (Due to release in 2020).
Column Access Strobe (CAS) latency, or CL, is the delay time of your RAM receiving a command and then being able to issue it. The numbers for the timings will look something like this; 15-17-17-35. Those numbers indicate how many clock cycles it takes for the RAM to respond to the command. However, faster MHz RAM with slower CAS timings might be slower than lower MHz RAM with faster CAS timings.
This is where it can be a little confusing, but let's try and simplify the data a little more.
Finding Your Real RAM Speed
Finding the real speed of your RAM comes down to a couple of factors, and has been embodied in a handy little formula. However, before we show you the formula, let's understand the different factors to consider when finding your RAM speed.
The first factor is the RAM clock speed; let's take 3200Mhz as an example.
The next factor relates to what RAM you have. For example, DDR (Double Data Rate) transfers data on both sides of the clock cycle. Meaning, it transfers data twice in one cycle.
And lastly, your RAM CL Timing, which is the first of the four numbers that make up the RAM timing. We'll use (14-15-15-39) for this example.
Those are the factors, so let's put them into an equation to work out the exact RAM speed.
You can use this formula to work out exactly how fast any RAM kit is - a great little tool to have in your locker.
By default, the maximum stock clock speed for DDR4 RAM is 2400 MHz. When you see RAM with speeds rated over this, it means the module has been overclocked to that speed by the manufacturer.
To access the RAM's boosted clock speed, you must first locate and enable the RAM's XMP/DOCP profile.
An XMP, or extreme memory profile, is a separate module that must be enabled within the motherboards BIOS to boost the RAM to its advertised speed. If you do not select the RAM's XMP/DOCP in the BIOS, your RAM will be running at a slower speed of 2400MHz.
It's always a good idea to make sure all of your hardware is compatible with each other as well.
Can I Mix RAM Speeds?
This question is a little bit of a mixed bag. The short answer is yes, but only sometimes.
RAM itself is compatible with other RAM of different timings and speeds. This being said, the greater the gap between the two speeds, the greater the stress your motherboard is going to incur trying to run them simultaneously.
For example, two modules of RAM with the same speed (let’s say 2400 MHz) and slightly different CAS timings probably wouldn’t be an issue. Your motherboard would pick the slowest one and run them both at those speeds.
The further away you get in speeds and timings, the harder your motherboard is going to have to work to run them together. Furthermore, it may require manual control over the speeds and timings in the form of over and underclocking the modules to ensure stability.
In other words, you could probably do it, but it would definitely be a bigger headache than it is worth.
Bandwidth & Capacity
RAM speed doesn’t exist in isolation; you also need to consider bandwidth and capacity when making a purchasing decision. Because of the number of factors, RAM bandwidth (and efficacy as a whole) can be a somewhat complex topic that’s deserving of its own article - something we might do in the near future.
As a concept, it’s relatively simple: bandwidth affects how much data can get through at any given time. And of course, memory is the space.
Some like to explain RAM as being like a highway. The bandwidth is like the number of lanes on the road; more lanes means more cars to go through. The speed limit represents the literal speed, and memory is like a big parking garage that all the cars are going in and out of, except in this scenario, the cars entering and leaving help you play video games.
Putting it simply, if you don’t have enough parking spaces, if the speed limit is too low, or if there aren't enough lanes on the highway then everything gets bogged down - and if you're following my riveting civil engineering metaphor, you understand that this is not great news for the performance of your system.
AMD APUs And Fast RAM
As many will know, the new batch of AMD processors are about to hit the market. With that in mind, we thought it would be suitable to touch upon how fast RAM boosts the performance of the new line of processors that are set to compete with Intel's for the first time in years.
Let's start with their APU range.
An APU, or accelerated processing unit, is AMD's answer to a processor with a powerful, built-in graphics card. AMD & Intel have both been designing some form of APU for years now, allowing customers to get a slice of both pies at a hugely reduced price. But how does an APU utilize faster RAM?
First, let's understand how an APU works. Unlike a PC that comes with a freestanding GPU, the APU has the graphics processor integrated into the CPU.
One of the benefits of having a standalone GPU is that it comes with its own super quick onboard VRAM to use when processing graphics. The APU, on the other hand, has to utilize your computer's system RAM - RAM that is already being utilized for other processes.
So, what's our point? Well, faster RAM, and more of it, is extremely beneficial to your APU system - faster RAM like the kind you would find onboard a GPU.
With AMD's CPU range, the story doesn't really change.
Since Ryzen was released, AMD has been making use of its impressive multi-threaded nature.
Multi-threading is when a CPU can double its cores by making use of virtual cores. If your CPU has six cores, it would have 12 threads, and so on. This being said, each thread will try to access your RAM, meaning quicker RAM will be more suitable to accommodate a multi-threaded CPU over say, an Intel CPU that doesn't have this facility.
We're currently in the process of putting together some benchmarking results of AMD vs. Intel and how faster RAM affects them in real-world situations. Stay tuned to see those results soon.
How Much Does RAM Speed Matter?
Alright, so we’ve figured out what RAM speeds are, how they work, and even how they affect your system. But how does RAM speed impact gaming? Is it worth buying RAM that’s rated a little higher to try and get those higher FPS counts?
This is a question the WePC team are asked all the time (and one that I've asked myself numerous times as well). For that reason, I decided to do some independent research.
Here’s the system I’ll be using for the tests:
- ASUS TUF X570 Gaming PLUS WIFI
- AMD Ryzen 9 3900X
- EVGA GTX 1080Ti SC Black Edition
- 16 G.Skill Trident Z RGB (CL16)
- Corsair Vengeance LPX 3200MHz (CL16)
- Corsair Vengeance LPX 3000MHz (CL15)
- Samsung 970 EVO M.2 SSD
Using this setup, I’ll be running six separate tests using eight different speeds/timing combinations:
- The G.Skill will be used to test "2666MHz CL11" "3600MHz CL16" "3600MHz CL14" "3800MHz CL16"
- We will use Corsair's Vengeance LPX 3200MHz module for "3200MHz CL16" "3200MHz CL14"
- And the Vengeance LPX 3000MHz for "2666MHz CL16" "3000MHz CL15"
Testing a range of RAM capacities, timings, and speeds will help give us a larger pool of information for both high-end and budget builds alike.
For benchmarking, I’ll be using the Time Spy demo from 3DMark to test both CPU and GPU and track FPS. I’ll be running the same test for each RAM configuration.
We'll also be accumulating in-game FPS from a number of different games which range from:
Counter-Strike: Global Offensive
The first game we decided to run was CS:GO, and not because it's my favourite competitive esports title either.
We went for CS as we knew it was a CPU intensive game and thought we'd see a variance in FPS across the different speeds and timings. However, as you'll soon see from the results, there was almost no difference across the entire range of tests we ran.
Stay tuned for further tests in this particular game
Far Cry 5
The Witcher 3
Total War: Warhammer II [Battle]
Forza Horizon 4
3DMark Time Spy
We finished by running 3DMark Time Spy to see if different configurations had any difference here.
What Speed RAM Should I Get?
So, on to the big question surrounding RAM speeds - which speed should I get?
Well, I suppose that depends on a number of different factors. As far as gaming is concerned, the most important component that affects frame rates is the graphics card. Ultimately, this will determine whether or not you're going to get 140+ FPS in AAA game titles. It'll also determine what resolution and settings you'll be able to push as well. Having said that, as you can see from the above data, getting the right RAM kit can make a huge difference.
|2666MHz CL16||2666MHz CL11|
|Far Cry 5||118||87||159||125||94||84|
|The Witcher 3||136||96||78||157||111||92|
|Total War: Warhammer II [Battle]||134||87||76||140||94||82|
|Forza Horizon 4||153||-||-||156||-||-|
|3DMark Time Spy||9759||10138|
|3000MHz CL15||3200MHz CL16|
|Far Cry 5||125||94||85||127||98||89|
|The Witcher 3||149||105||86||150||104||85|
|Total War: Warhammer II [Battle]||140||92||82||141||93||85|
|Forza Horizon 4||158||-||-||158||-||-|
|3DMark Time Spy||10033||9955|
|3200MHz CL14||3600MHz CL16|
|Far Cry 5||136||104||96||126||95||87|
|The Witcher 3||168||118||93||153||109||85|
|Total War: Warhammer II [Battle]||146||101||90||143||96||86|
|Forza Horizon 4||162||-||-||157||-||-|
|3DMark Time Spy||10156||10026|
|3600MHz CL14||3800MHz CL16|
|Far Cry 5||141||111||99||135||105||94|
|The Witcher 3||178||124||97||170||121||94|
|Total War: Warhammer II [Battle]||149||105||95||147||103||90|
|Forza Horizon 4||162||-||-||160||-||-|
|3DMark Time Spy||9901||10138|
|3600MHz CL14||3200MHz CL16|
|Far Cry 5 [ULTRA]||130||102||92||117||90||84|
|The Witcher 3 [ULTRA]||162||108||77||145||101||72|
Before we talk about the differences, let's quickly brush over where RAM doesn't seem to make a difference in performance. The 3DMark Time Spy test seemed to showcase very little to no effect when under different RAM speeds or timings. Furthermore, CS:GO was also unaffected by differing configurations.
Where you will see RAM speeds benefit you, however, is in the newer titles from the last few years. Every other game we tested showcased the same increase in performance across the board. Interestingly, we saw a dip in performance when reaching 3800MHz. We'll discuss this in more detail shortly, but the bottom line is: tighter timings are better than faster speeds.
It's also worth mentioning that better speed and timing configurations are going to make multi-tasking scenarios much more accessible - think streaming and rendering.
To make your life a bit easier, we've compiled the essential pieces of information from this article and have laid them out in bullet point format. These are staples that you should consider when purchasing new RAM, especially if you're looking to increase in-game performance:
- Tight timings > Speeds: The clear pattern in all of our tests were found within the tighter times. By tightening the times, you improve FPS across most of the games exponentially. Well, I say exponentially, you'd probably still be better off putting the extra cash towards a better GPU. But for those that already have a top of the line card, this is certainly a way of squeezing extra performance out of your build.
- The Sweet Spot: This might spark some speculation, but from our results, the best way to maximize in-game performance (from RAM) is to purchase a 3200MHz kit and tighten the timings right down. You'll save a decent amount by opting for 3200MHz over 3600MHz, and once you've tuned in the timings, the difference isn't that wide.
- Not messing with the timings?: If you plan on getting RAM and using it straight out of the box, we recommend getting the cheapest 3000MHz+ kit you can find. All the tests suggested that out-the-box speeds made very little difference (less than 1% in most cases) to in-game performance.
So we’ve learned how RAM works, what the speeds tell us, and we’ve even looked at some benchmarks to find out exactly how it affects your system when it comes to graphical tasks vs. processor tasks.
I'm currently running 16GB of 3600MHz RAM for my personal gaming computer, and it never misses a beat. Whether I'm playing one of the latest AAA game titles or doing some fairly intensive video editing, 16GB is more than enough to keep my system running at optimal levels.
Lets us know what RAM speed you're currently running and if this article helped in any way. Better yet, head on over to our Community Hub, where you can start a thread and discuss everything RAM related.