Bottlenecks are extremely annoying because it prevents your hardware from running at maximum performance, this can ruin many experiences.
We’re well aware of the CPU/GPU bottleneck, but the RAM/CPU bottleneck is more subtle, and can actually reduce performance by quite a bit.
In general, the RAM can actually bottleneck the CPU, and it can reduce performance significantly especially when gaming, it’s usually caused by slow memory speeds.
What Is Bottlenecking?
Bottlenecking is defined by the functionality of efficiency of a program or hardware component being limited by an external component.
The most common example of a bottleneck is the CPU bottlenecking the GPU, this is caused when the CPU is extremely slow in contrast to the GPU.
Bottlenecking will always exist, it’s impossible to completely remove bottlenecks or computers would have infinite performance.
The best thing you can do is minimize its effects by building a well balanced system, don’t pair a super powerful GPU with a really weak CPU.
What Causes A RAM & CPU Bottleneck?
When RAM bottlenecks the CPU, it’s mainly due to the RAM not being able to keep up in terms of speed and capacity, this can usually be fixed by buying more or faster RAM.
RAM bottlenecks can cause massive problems for the entire system because the CPU has to wait longer for instructions which cause it to slow down.
So when you’re gaming and you have a RAM bottleneck, you will notice this in the form of stuttering and FPS drops which can ruin the gaming experience.
Not having enough RAM capacity can also bottleneck the CPU, and this is probably the worst form of a RAM bottleneck.
This is because the CPU will have to go to the permanent storage which is the SSD and the HDD for instructions, and the permanent storage is magnitudes slower than RAM.
RAM Has The Potential To Bottleneck Ryzen More
When it comes to Ryzen processors, the speed the RAM operates at is more of a concern, this is because Ryzen processors are more sensitive to RAM speeds.
So if your PC is Ryzen based, you must ensure that the RAM you have is fast enough, but it’s more complex than that.
With Ryzen based processors, you mostly want your Infinity Fabric Clock(FCLK) to match the value of the memory clock (MEMCLCK) and your unified memory controller clock in a 1:1:1 ratio.
With this perfect synchronization, it can result in up to a 5% performance boost due to having less of a latency penalty.
With Intel, you can usually get away with slower RAM speeds 3200MHz is usually ideal, but with Ryzen, you may want at least 3600MHz or faster.
How To Fix A RAM & CPU Bottleneck
To be able to fix a RAM bottleneck on the CPU, you must first identify how the RAM is bottlenecking the CPU, there are usually two ways it can.
The first way the RAM bottlenecks the CPU is by speed, when the clock speed is too low it causes low bandwidth, which can cause the CPU to slow down due to a lack of instructions being sent by the RAM.
To fix this, you usually need to purchase faster RAM, XMP RAM is pretty great at dealing with this issue because it’s easily overclockable.
The second form of RAM bottleneck has to do with the capacity, when you don’t have enough RAM capacity, the CPU will use the permanent storage as RAM.
To fix this form of bottleneck, you usually have to purchase more RAM, the recommended RAM capacity nowadays differs between tasks.
For gaming, the recommended RAM capacity is 16GB, this is because most games aren’t actually RAM intensive except for simulation and modded games.
For video editing, the recommended RAM capacity moves up to 32GB, and it only gets more demanding the higher the resolution you video edit at.
Does RAM Speed Affect FPS?
Yes, RAM speed seemingly does affect the amount of FPS being generated. The faster your RAM is, the more FPS will be generated.
But it doesn’t just affect the average frame rate, the 1% lows in video games are significantly higher which makes the game more smooth with less stutters.
For the best gaming experience we recommend 3200MHz, higher is definitely better, but this should be enough for most CPUs.
As you can see from the screenshot above, the build with the 3200MHz RAM config average frame rate is 28 frames higher than the 2133MHz config.
In many games, 28 FPS is a significant difference, and it could make an unplayable game much more playable, for example, FPS games.
What Is The Best RAM Speed?
If you want to make sure you don’t get bottlenecked by your RAM in terms of RAM speed, then the minimum recommended speed is 3200MHz.
For Intel processors, 3200MHz should be enough, it should be able to keep up with most Intel based processors.
For Ryzen based processors, 3600MHz is the recommendation because Ryzen processors are significantly more sensitive to RAM speed, so you’re more likely to bottleneck a Ryzen CPU.
With DDR5 RAM being freshly released, they have the potential to be significantly faster than DDR4 memory, the fastest DDR5 RAM module is 6000MHz.
Can The RAM Bottleneck The GPU?
The RAM can actually bottleneck the GPU, but the effects are usually minimal, you mostly hear about the RAM bottlenecking the CPU.
But the RAM can indirectly bottleneck the GPU because the GPU has to wait on the CPU, and if the CPU is waiting on the RAM, then technically the RAM has bottlenecked the CPU.
When buying RAM ensure that it has enough capacity for the task you want to run, then ensure the speed is fast enough, this is really important for Ryzen CPUs.
That’s really all that matters, 16GB of RAM should be enough for most tasks, and 3200MHz should be enough for most CPUs, this should be enough to minimize most bottlenecks.
If you want to identify if your RAM is bottlenecking your GPU, use overlaying software in a demanding game to see if your GPU is running at 100% usage.
If not, then there’s something bottlenecking the graphics card, if you have a decent CPU in terms of single-core performance, then your RAM is most likely the culprit.
In conclusion, the RAM can be a huge bottleneck, and result in performance loss if you don’t consider the capacity and the speed of the RAM.
To make sure you don’t have to worry about RAM bottlenecks, purchase at least 3200MHz DDR4 RAM for Intel, or 3600MHz DDR4 for Ryzen.
And just ensure that the capacity of your RAM is enough for what tasks you want to perform, but 16GB should be enough for most tasks.