Can CPU Bottleneck RAM [Unveiling the Bottlenecking Truth]

Written By Farhan Max

Bottlenecking can be painful when you’re seeking high-level performance from your rig. And you might have already faced CPU bottlenecking the GPU or vice versa.

But can a CPU bottleneck RAM?

Technically, It’s possible for a CPU to bottleneck RAM, and there are solid reasons behind it. So, let me clear up this factor for you through this

So, let’s start reading without further ado.

What is a Bottleneck in PC?

The bottleneck in a PC refers to when a specific component is limiting another component from delivering high performance. The term bottleneck is common for PCs, and this happens mostly when you pair low-tier hardware with higher ones. Therefore, bottlenecks affect PC’s performance badly.bottleneck-in-pc

The bottleneck is everywhere, not only in your PCs, and you’ll also find it in your car, AC, Wi-Fi, and even in your body. Suppose your Wi-Fi router is only capable of transmitting data at a maximum of 150Mbps, but the broadband line you’re using provides more than 450Mbps.

So, your router is the device that’s bottlenecking the broadband speed.

Suppose you are running a PC with a high-end GPU and low-end CPU. The CPU won’t be able to provide the data that is required by the GPU while rendering high-level images. As a result, the GPU is bottlenecked by the CPU. So, mismatched hardware will trigger a bottleneck for sure.

As I stated earlier, bottlenecking is everywhere, and I can give tons of examples of this. But let’s get into the main concern of this article, whether it’s possible for the RAM to be bottlenecked by the CPU.

Can a CPU Bottleneck RAM?

A CPU can bottleneck RAM if the CPU can’t utilize the RAM to its full speed. This will happen when a low-powered CPU is limited to using RAM at a fixed bus speed. The main point is the RAM’s speed is combined with the CPU’s performance; that’s why a low-end CPU will bottleneck a faster RAM.can-a-cpu-bottleneck-ram

Speaking of RAM with higher bus, not all the processors are overclockable, and Intel’s unlocked CPU can use only a limited speed of RAM.

Suppose you’re running an Intel Core i5-9400, but you installed 8 gigs of 3200MHz DDR4 RAM. When you launch Adobe Premiere Pro to edit videos, the RAM will catch the bottleneck.

Because the Premier Pro is a heavy app for video editing, and it is facilitated by using a higher RAM speed/frequency. But 9th Gen Core i5-9400 is locked to use the RAM only at 2666MHz, and this is the highest speed the CPU can work with.

The reason is you can only overclock the Intel K series CPUs. All the non-K processor doesn’t support overclocking, and you can’t extract the maximum performance from your RAM.

So, RAM can’t deliver its top speed despite a lot of demand due to a locked CPU. However, RAM is low on the list of bottlenecks, but things can go wrong at any time. So, before purchasing RAM, ensure what is the maximum RAM frequency your CPU supports.

And if you do have an overclockable CPU or purchased one, you can increase the RAM speed to remove or reduce the bottleneck.

Does RAM Speed Bottleneck the CPU?

RAM bottlenecking a CPU is the most common scenario for a PC user who didn’t install sufficient RAM. Heavy app users or AAA-titled gamers must need more RAM along with a high-end CPU & GPU. That’s why insufficient RAM, high latency, or low bandwidth can bottleneck a CPU.

Modern apps and games can utilize more RAM to achieve higher performance. For that, gamers must need compatible RAMs that come with low latency, as it facilitates gaining more speed.

So, when a RAM bottlenecks a CPU, there are mainly two reasons behind it. The first one is RAM capacity, and the second one is bandwidth or speed. But the amount of RAM you require mostly depends on the workload.

To handle more workload, you must need sufficient RAM. You require at least 16 gigs of RAM in terms of gaming to avoid bottlenecking the CPU. And for video editing & rendering, you must install at least 32 GB of RAM to handle a massive workload along with CPU & GPU.

If you’re an AMD processor user, you know AMD Ryzen processors are thirsty for RAM speed. You need at least 3600MHz DDR4 RAM to use the Ryzen processors at their maximum efficiency. And lesser than this speed will bottleneck the APU for sure.

So, low RAM bandwidth is a factor in bottlenecking a CPU.

Another factor is if you are using highly graphics intensive works without having a dedicated GPU, RAM will add up its memory with the iGPU to handle the workload because iGPUs are not that strong. For this, the CPU requires more graphical processing power.

That’s when a large amount of RAM adds as shared GPU memory. Due to this shared GPU memory, you won’t have enough available RAM for handling high workloads, and a bottleneck occurs at that instance.

Faulty RAM can sometimes bottleneck a CPU. So, check for faulty RAM and take the necessary steps. If you want to buy another RAM, ensure its speed is supported by the CPU.

While buying RAMs, you might notice the RAM speed is advertised sometimes with MHz and sometimes MT/s. Well, don’t think these are the same. There are differences between MHz & MT/s of a RAM speed.

How to Check for a Bottlenecked RAM

If you’re having a bottleneck issue, you must check it by monitoring the component’s usage when they are under load. For checking, you can use the Windows built-in Task Manager. It’s a perfect tool for monitoring CPU, GPU, or RAM usage when all are working simultaneously. For GPU usage monitoring, you can go for the MSI Afterburner. It’s a perfect app for graphics card overclocking and monitoring. Now, let me show you how to check for bottlenecking RAM caused by the CPU from the Task Manager.

Here are the instructions to check CPU bottlenecking RAM by monitoring usage from Task Manager:

  • Press Ctrl + Shift + Esc at a time to launch Windows built-in Task Manager.
  • Click on the Performance tab. You’ll see CPU, Memory, Disk, Wi-Fi or Ethernet, and GPU categories in the left pane.
  • Select the Memory section and look for the In use and Available section.
  • Keep an eye on the CPU usage from the left pane as well.Check-cpu-and-ram-usage-from-task-manager

If the CPU usage is high and RAM usage is low, then the CPU is bottlenecking the RAM. The CPU won’t be able to use more RAM if the processor is already maxed out.

Now, it’s time to overclock the CPU or go for another one. Sometimes, running a CPU with only single-channel RAM can provoke this issue because today’s processors need dual-channel memory to work at its maximum efficiency.

However, there is a quad-channel mode, and those are mainly for workstation-based processors. Mid-range gaming motherboards do come with four RAM slots but don’t mix that with quad-channel.

Those four RAM slots are mainly for dual-channel memories, and you must know how to use RAM slots for installing RAMs.


Can CPU affect RAM speed?

If the processor’s speed is not enough to handle the high speed of the RAM, the CPU will bottleneck the RAM.

How to know if the CPU is bottlenecking the RAM?

To know the CPU is bottlenecking the RAM, launch Windows Task Manager. Go to the Performance tab, and keep an eye on the CPU and Memory usage percentage from the left pane. If the CPU is at 100% whereas the Memory is below 60% then the RAM is being bottlenecked by the CPU.

What happens when RAM is too fast for the CPU?

If the RAM’s speed is higher than the CPU can support, the RAM’s speed will be locked at the CPU’s maximum supported bus.

Bottom Line

RAM bottlenecking is ironic when you’re playing games, and it will give you nothing but glitches and stuttering. Sad, but the truth is sometimes the CPU can make RAMs bottleneck, and it’s awful.

If you’re facing this, upgrade the CPU that can handle higher RAM speed or utilize more RAM. Also, look for a fault in the RAM with a good RAM testing app like the MemTest. I hope doing this will solve the problem for you.

For additional help, knock me in the comment box. Best of luck & see you at the next one.

About The Author
Farhan Max is a tech geek with a particular interest in computer hardware. He's been fascinated by gaming since childhood and is now completing his undergraduate studies while researching and testing the latest tech innovations. Alongside his love for all things geeky, Farhan is also a skilled photographer.

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