EXPERT INSIGHT & TRUSTED REVIEWS

The Complete Guide to RAM Speeds

Kaelum Ross

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Dec 22, 2020

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When you’re looking to build your PC and you’ve arrived at selecting RAM, it can feel overwhelming to know the right GB, MHz, and CL measurements for your needs.

This is why today’s What in Tech feature will be taking you through everything you need to know about RAM, from common speed versus speed questions and which spec matters most in your decision.

We’ve also included the best RAM choices available with different budgets in mind.

This is a long guide, the contents table below is your friend! Look specifically for the questions & recommendations that interest you instead of reading top to bottom!

Table of Contents

What is RAM Speed?

For the average PC builder, the capability of Random Access Memory (RAM) is measured by 3 key fundamentals: frequency, latency, and size (technically, size isn’t speed-related – but for the purpose of establishing what RAM is best for you, we’ll be covering it).

RAM Capacity / Size

RAM size is, as the name suggests, the overall capacity of the memory you’re buying. 4GB, 8GB, 16GB, and 32GB are the most common sizes right now.

Additional capacity means your PC will have the ability to run more programs simultaneously/switch between them more smoothly.

This is where the name “Random Access Memory” comes in. Your main storage (Solid State Drives, Hard Drives, etc.) are designed to offer much larger storage but are slower than RAM, which is why those drives are store your data and require a more significant loading time when opening them for use.

Once software/games/files are open, they then utilize your PC’s RAM, which is faster than your SSDs/HDDs, so that they can be “randomly accessed” quickly during use.

A common metaphor to explain the difference is that RAM size is almost like your desk, and the more capacity you have, the larger your desk is (meaning you can have more items in arms reach ready to quickly use).

While your hard/solid-state drives are the size of your shelves, drawers, and cabinets; these are used to store most of your items and take a little longer to take out for use on your desk.

Generally more RAM capacity is better, but there are diminishing returns (we’ll get back to that).

RAM Clock Speed / Frequency

Clock speed or frequency is a RAM’s MHz rating (nowadays, most RAM will be in the 2400Mhz to 4400MHz range).

Faster clock speed allows your processor to retrieve data located on your storage drives more quickly. Reducing the time it takes the CPU to access this data increases your performance in real-world scenarios and games.

Clock speed is measured in Megahertz (MHz) which indicates how many times per second your RAM can access its memory (as you probably expect, more is better, but we’ll speak further below about the sweet spot between price and utility).

CAS Latency

The last key part of the equation is Column Access Strobe or CAS latency (often just “CL”) which is integral in understanding RAM speed and often overlooked compared to a stick’s MHz rating.

CL indicates how long it takes your RAM to recognize a command/action (similar to how a monitor has latency between receiving your mouse click and outputting the result visually).

The latency is usually recorded by 4 numbers in the following format: 16-18-19-30 which represents the number of clock cycles it takes for the RAM to register a command. It is the first number from the 4 that is typically used to establish CL. Nearly all popular RAM today is between CL 12 & CL 18 (mostly CL14-16).

We talk more about how to balance latency and clock speed below. But to demonstrate why both are important, think about it: if you have very fast RAM, but the latency is high, it would be like gaming on a high-refresh-rate monitor but each of your actions takes a second to register (a dramatic example, but you get the point…).

DDR4 RAM Speed Vs 1

How much does RAM Speed Matter?

So, we’ve established at a high level what the integral parts of RAM are for your build.

But how much does RAM speed matter?

The short answer is that for business and personal use (web browsing, e-mails, basic software, Netflix, etc), you’ll likely be fine with any 8GB (ideally 16GB) RAM from a reputable manufacturer.

If you’re into gaming or plan on using your build for production work like video editing, game development, or rendering, then the speed can have a more notable impact.

How much does size matter for RAM – 4GB vs 8GB vs 16GB vs 32GB

Of all the specs, size matters the most.

So if your battle is faster RAM vs more RAM (i.e. CL / MHz vs GB), we’ll nearly always recommend the latter option.

That said, RAM size does have diminishing returns. 16GB is what we recommend for nearly all users, 8GB for tighter budgets, and 32GB for high-end enthusiasts. Beyond that, there isn’t really much use (even 32GB is pushing past the realm of necessity unless you’re doing production work). If this sounds confusing, we detail the best RAM options towards the bottom of this guide.

How much does RAM clock speed matter?

Clock speed matters, but not as much as you may think.

You can build a powerful gaming PC with 16GB 2400MHz DDR4 RAM for instance (which is on the lower side of clock speed). Would it be better to have say, that 16GB of RAM at 3200MHz+? Absolutely! But it’s not a deal-breaker to have lower speeds if your budget is tight or you’re simply not bothered about fine-tuning potential performance/game FPS.

If you’re building a PC purely for basic business and personal use, we would suggest that cheap RAM will suffice for you as long as the size is large enough.

We do however see lots of unanswered questions from users around the difference between X MHz and Y MHz RAM. Which is why further below, you’ll find our comparison list as a quick guide to help you decide between two types of memory.

How much does latency matter for RAM

The most overlooked RAM speed factor, CL, is kind of like clock speed; it matters, but shouldn’t be a huge deciding factor in your PC building decisions.

A higher latency RAM (say, CL18) could still be perfectly decent if its other specs were around 16GB/3200MHz, RAM size is still the most important thing overall.

That isn’t to say that if you see CL12-CL14 RAM, you shouldn’t absolutely go for it if the other specs are decent (especially if you’re building a gaming PC or something for production work). But in the context of price/value, these low latency sticks are often 30%+ more expensive, which we can’t say is worth it unless you are trying to build the all-around most powerful computer possible.

DDR4 RAM Speed Vs 2

RAM Speed Comparison FAQ

DDR3 vs DDR 4 – How much faster is DDR4

DDR4 is essentially the next natural iteration from DDR3. With significantly great size capacity & higher clock speeds, 4 is notably faster in nearly every case (latency is slightly higher on 4, but is made up for with the other specs).

In nearly all cases today, we would say pick up DDR4 RAM. It is overwhelmingly what the current market motherboards/CPUs are best compatible with.

The right question isn’t really “is DDR4 worth it” anymore in terms of speed. Because of its widespread market adoption, prices on this RAM are great. You’ll typically be getting faster RAM with little consequence compared to DDR3.

The only scenario we see DDR3 as worthwhile today is if you’re building an ultra-cheap PC and have specifically found a motherboard/CPU combo that supports 3 and not 4 (we don’t like this from a future-proof perspective and would try to stick to 4, but it could make sense if you need to be as cheap as possible).

DDR4 vs DDR5 RAM?

DDR5 RAM is in development and will offer 50-100% higher clock speed than DDR4, a slightly lower voltage and individual RAM sticks that can go up to 64GB each (the max with DDR4 is 16GB).

This sounds great on paper. But at this time, these ultra-high clock speeds/sizes lead to huge diminishing returns in pretty much all PC activity (we talk more about this in our comparison of higher MHz RAMs further below) so in reality, that 50-100% “theoretical” performance increase may not be super noticeable unless you’re building a very high-end machine (and in nearly all cases, the money would be better spent on a better CPU/GPU).

DDR5 RAM is scheduled for mass release in 2021. Though we recommend keeping expectations measured, as the DDR5 release date has been a moving goalpost for a couple of years now.

And even when the RAM is released, you can still expect a long-delayed period where motherboards, CPUs, and other PC hardware manufacturers take time developing new products that adopt DDR5 as the standard and take advantage of its speeds.

To sum up, while the difference between DDR4 and DDR5 RAM sounds exciting, we really don’t think it’s relevant to builders for the next few years. Stick to DDR4 for now.

What RAM Speed should I get?

The million-dollar question! Unfortunately, the answer isn’t clear-cut, as it depends on your budget and requirements.

A reasonable rule of thumb is to commit to at least 16GB RAM size-wise. Then from there, try to aim for a balance between CL/MHz between CL14 2666MHz & CL16 3200MHz.

To make it easier for you, the bottom of this guide details the best RAM picks today. If you want more autonomy on your choice, we’ve built the RAM speed quick-reference list further below too.

More RAM vs Faster RAM (Size vs MHz/Latency) 

We’ve touched on this already, but it’s worth re-iterating: size is way more important than MHz & latency for nearly all users.

As an example, 2400MHz 16GB RAM will be better than 3200MHz 8GB RAM. The only time we’d pick MHz/latency improvements in this kind of bracket is if your remaining budget can’t jump up to a larger size, but could be squeezed slightly further to accommodate faster sticks.

The other exception to this rule is if you’re buying very large RAM. If you have 32GB in memory, we can’t imagine more will be required for a long time (unless you’re creating a very high-end production machine). At this point, if you still have the budget, it will be usually better to focus on faster 32GB RAM than slower 64GB+ memory.

MHz vs Latency – which is more important for RAM speed?

The difference between MHz and CAS latency value is a difficult question as the best approach is for there to be a balance between these 2 factors (instead of very fast frequency/slow latency or vice versa).

The “sweet spot” for most users today (particularly gamers) with the price in mind is around CL14 2666MHz to CL16 3200MHz.

Now you can fall outside of these balances (e.g. plenty of RAM sticks offer CL18 latency but make up for it with significantly more frequency or lower prices) but we would use that range as the rough spot to go in unless you’re building something high-end and are trying to get extra-low latency and high MHz.

RAM Speed Importance for Intel vs AMD

The main function of RAM speed is to empower your CPU and its ability to retrieve/store randomly accessible data easily.

So your CPU is indirectly an important factor in deciding how much to invest in RAM speed. For example, if you’re buying a high-end CPU, you’ll achieve more value from spending extra on fast RAM (as lower speeds can bottleneck certain CPU operations).

When it comes to the Intel vs AMD builds, it’s complex as the impact on speed depends on the chipset & model version. But as a (mostly reliable) rule of thumb: AMD CPUs/builds benefit more from better RAM speeds than Intel due to the way its memory controllers operate.

This is not to say RAM speed doesn’t matter for Intel CPUs however. We’ve seen many RAM benchmarks show games and various software processes perform notably better with higher frequency/lower latency memory on Intel chipsets.

CL 12 vs CL 13 vs CL 14 vs CL 15 vs CL 16 vs CL 17 vs CL 18

Our comparison list just below focuses on the difference between MHz as we often see reader questions specifically asking about the frequency differences.

But as made clear in this guide, latency is as important as the frequency in deciding RAM speed. 

For example, the difference between CL14 and CL16 is usually more significant than the difference between 3000MHz and 3200MHz. But focussing all on latency (or all on clock speed) introduces diminishing returns, which is why considering both factors is important.

Unfortunately, it’s not a simple balancing act between the two measurements, as you’ll often see companies sacrifice low latency for high speed, or charge a lot more to ensure both specs are good.

We’ve detailed some of the best RAM available today at the bottom of this guide to make it easier for you. But if you do want to decide yourself, we would try to stick to the previously mentioned “sweet spot” of between CL14 2666MHz to CL16 3200MHz for mid-range builds, or you can seek faster/lower latency sticks if you have the budget.

DDR4 RAM Speed Vs 3

RAM Frequency Comparison Quick Reference List

RAM Frequency/Speed Comparison Chart (How to use)

We appreciate that despite all the info/FAQ answers above, many manufacturers produce things in a large array of different frequencies/MHz and you may be struggling to choose between 2 or 3 narrowed options.

We’ve created the below reference list as a quick guide to help you on the most common user head-to-heads based on RAM speed benchmarks.

Don’t feel the need to read every one of these – it’s just for quickly assessing the difference between speeds if you have 2 in mind!

CL / Timing vs MHz / Frequency

The below list assumes that every RAM stick you’re looking at is the same CAS Latency. 

It’s important to note that for computer processes (especially games), while higher RAM frequency and lower CL timings are always better, there is usually a “sweet spot” for mid-range budgets, otherwise, you risk buying RAM sticks with high speed but high CL timings (or vice versa).

For example, CL14 3200MHz RAM would be better for gaming than CL16 3600MHz RAM, so make sure to balance picking between both.

If that sounds complex, don’t worry! Just below the comparison list, we’ve included the best RAM choices depending on your budget level.

RAM Frequency Comparison List

DDR4 2400MHz vs 2666MHz

2666mhz will provide a slight improvement over 2400mhz (particularly in AMD builds).

For gaming, this will translate to a couple of extra FPS in some CPU-intensive titles (i.e. only go 2666MHz if it’s close to the same cost).

DDR4 2400MHz vs 3000MHz

The speed difference between DDR4 2400MHz and 3000MHz still won’t be huge for a lot of gamers/other users but will be a fair bit more noticeable than 2666MHz.

Providing the RAM you’re eying has good latency (and size) you can expect 3000MHz to be the better choice if the price is only 0-10% extra.

DDR4 2400MHz vs 3200MHz

3200MHz RAM is a popular speed for many gaming RAM manufacturers. Combined with a good latency, this will often be a happy medium to ensure you don’t bottleneck a mid-range CPU motherboard combo.

2400MHz would be fine for cheaper builds but we’d recommend 3200MHz if your budget can accommodate it.

DDR4 2400MHz vs 3600MHz

If you are getting a high-end CPU, we’d recommend going with at least 3600MHz to ensure the RAM isn’t indirectly bottlenecking the performance during any processes.

If your budget is tight, you’ll be better off with 2400MHz and spending your money on at least 16GB of RAM size.

DDR4 2666MHz vs 2667MHz

The difference between DDR4 2666MHz and DDR4 2667MHz is non-existent. This is simply a marketing term used by companies who round up/down differently.

Buy whichever one is cheaper (assuming size/latency are the same).

DDR4 2666MHz vs 2933MHz

You may achieve an extra couple of FPS in games that are heavy on CPU requirements, but for the most part, there won’t be much difference between 2666MHz and 2933MHz.

2933 MHz also isn’t as popular for RAM manufacturers so we’d expect 2666 MHz to be more cost-effective (or if you do want higher, look at 3000MHz).

DDR4 2666MHz vs 3000MHz

Similarly to 2666MHz vs 2993MHz, the difference in speeds isn’t wide enough to be that noticeable so only pick up 3000MHz if it’s very close in price or you are keen to min-max gaming FPSs (if that’s the case, you may be better with the higher speeds further below).

DDR4 2666MHz vs 3200MHz

RAM speed increase of 3200MHz over 2666MHz will be a little noticeable/may achieve a few extra FPS on CPU-heavy games (or improve runtimes during certain processes, particularly for high-end processors and especially AMD Ryzen CPUs).

DDR4 2933MHz vs 3000MHz

While the difference between 2933MHz and 3000MHz isn’t non-existent, it’s pretty close to being completely meaningless for most builders (almost certainly <1 average FPS increase in all games at the most). We’d go with whatever sticks are cheaper/have better latency. 

DDR4 3000MHz vs 3200MHz

You can expect a slight, modest speed increase when comparing the difference between 3000MHz and 3200MHz RAM, but don’t expect this to be more than a couple of FPS extra in processor-heavy games. So stick to whichever one is cheaper if all other specs are equal.

The one other thing to point out is that 3200MHz is a little more popular for RAM brands to produce, so your options might be better/more cost-effective.

DDR4 3000MHz vs 3600MHz

With a 20% MHz increase, at this point, you can expect the difference between 3000MHz and 3600MHz to be a little noticeable, albeit not essential if the 3000MHz RAM is notably cheaper (10% or more).

We like speeds of at least 3600MHz if you’re purchasing a high-end CPU (especially Ryzen/AMD) because these can occasionally be bottlenecked by lower frequencies in some operations (but we are min-maxing here, 3000MHz will be fine for most people).

DDR4 3000MHz vs 4000MHz

Is 4000MHz worth it over 3000MHz? Well, you can expect a nice performance jump in a lot of work-related processes (think rendering, editing, and other high-end production).

For gaming, RAM speed benchmarks tend to show around a 5% average FPS increase between these two frequencies. This is a nice jump, but if an FPS increase is your only focus, then the price difference may not be worth it. 3000MHz is enough for gaming on a budget/mid-range build.

DDR4 3000MHz vs 4400MHz

With nearly 50% extra frequency, there are certainly some notable improvements between these two frequencies. While you can expect a good performance increase in games (5% or so for many titles), the real value of going beyond 4000MHz will be in other processes like video editing and rendering.

But in real-world terms, we know a reader’s real question will usually be “is 3000MHz RAM good enough for gaming”. And the short answer is yes, you’ll likely see diminishing returns cost-wise unless you’re running a high-end processor; so 4400MHz will not be worth it for budget/mid-range builds unless the cost is similar (if you want higher 3600MHz-4000MHz will give you similar gaming results).

DDR4 3200MHz vs 3600MHz

If possible, we’d recommend at least 3600MHz if you are doing some high-end production work (rendering, video editing, etc.) and are invested in the time processes take.

For gaming, 3600MHz may be slightly better for CPU-intensive games, but not particularly notable (i.e. not worth paying more money for if FPS is your only focus as we fine 3200MHz is often the best value for RAM).

DDR4 3200MHz vs 4000MHz

Similarly to the difference between 3000MHz and 4000MHz, you can expect something close to 5% increase in many CPU heavy games, whether you think this is worth it is really down to your personal opinion and the price difference (we will say that 3200MHz is the most popular RAM speed today, so often has some good offers from big RAM manufacturers).

The real value for most users will come from if they do high-end work on their setups like video editing and other production. Unless you’re building a premium gaming PC, we don’t think the difference will be too important here.

DDR4 3600MHz vs 4000MHz

As discussed in earlier speed comparisons, RAM speed benchmarks for 3600MHZ, 4000MHz, 4400MHz, and beyond have shown that there begins to be diminishing returns for gaming.

If you have a high-end CPU (especially Ryzen), then you may get your money’s worth, but otherwise, we’d only recommend 4000MHz+ for video editors and intense computing.

DDR4 3600MHz vs 4400MHz

For gaming, the difference between 3600MHz and 4400MHz is small for most titles as there is diminishing returns at this frequency level for most titles (the only exception being if you’re running a very high-end AMD CPU to avoid any slight bottlenecking) therefore we’d only say 4400MHz is worth it if you are focussed on making your high-end production/editing work more efficient.

DDR4 4000MHz vs 4400MHz

We wouldn’t consider the difference between 4000MHz and 4400MHz RAM for gaming important (unless you really want to future-proof RAM, but we’d say it would be more cost-effective to buy cheaper and upgrade to DDR5 when it is popular in a few years).

For video editing, rendering, and other production work, you can expect to see a little jump in performance and it may be worth it if the price increase is in the realm of 10-15%.

DDR4 4400MHz vs 4600MHz

A difference of less than 5% frequency at these high levels is really not that integral to any performance, whether you’re building a gaming rig or a high-end production setup.

4600MHz is only worth it if it is very close to the same price as the 4400MHz sticks.

DDR4 RAM Speed Vs 4

The Best RAM for Gaming and Other Builds

Feeling overwhelmed by all of this detail? Don’t worry, here’s our quick list of the best RAM picks available today for varying budgets.

Overall Best RAM for Gaming: Crucial Ballistix 3200 MHz DDR4 16GB

Great value, decent speeds, good size and from one of the best RAM brands, this Crucial set ticks all the boxes we think a gaming (or mid-range production) PC will need.

Best Budget Gaming RAM: OLOy DDR4 16GB RAM

At a very impressive value point, this OLOy RAM will suit most gamers on a budget who will be better placed spending extra on more expensive GPU/CPUs where possible (the manufacturer isn’t as reputed as say, Crucial, but this memory has been well received from a lot of budget PC builders).

Most Powerful RAM for High-End PCs: G.Skill Trident Z Neo Series 32GB

At an impressive 3600MHz, CL16 with 32GB of size, the G.Skill Trident Z Neo is a fantastic offering for high-end gaming or production builds.

Yes, you can get technically do better than this, but diminishing returns will start to kick in more dramatically, our pick is based on still providing decent value despite this being an expensive set of memory.

Cheapest RAM: V-Color 8GB DDR4 RAM

Technically you can go cheaper with 4GB, but even if your build is just for business and personal use, we would recommend this great-value V-Color 8GB RAM as a minimum.

Being a single stick, you’ll also have the opportunity to add a second 8GB piece at a later date. Even at its small size/slightly lower speed, this memory will get a budget gaming build off the ground (if you’re very tight on money, it’s probably going to be best to invest in a better CPU/GPU and upgrade your memory later).

Final Word

We’ve been over a lot of queries in this feature, and appreciate that learning about how to compare MHz, latency, and GB speeds can be a lot to take in.

So while we did make this guide to inform readers and give you the ability to maximize value from your RAM purchase, we’ll reiterate: the most important aspect is size.

If you buy one of our top picks above, or pretty much any DDR4 16GB+ RAM set, you will still get decent performance. So hopefully you’ve got what you need to know, but if RAM speed stresses you out, go with one of our recommendations or pick a popular 16GB gaming RAM choice, and move on to stressing about GPUs, CPUs, motherboards, and PC cases instead!

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