PCIe 4.0 vs 5.0: The Ultimate Guide In 2026

Do you want to understand the main differences between PCIe 4.0 and 5.0 and how to make a reasonable choice between them? Don’t miss this guide; you can easily come up with the answer you want: PCIe 4.0 vs. PCIe 5.0. Which one is better for you?

Introduction

If you have ever built a PC before, then you will probably be aware of the long horizontal slot or the PCIe slot in your motherboard. PCIe, or Peripheral Component Interconnect Express, is a high-speed serial interface standard designed to establish high-speed communication between the CPU and peripherals, mainly graphics cards, sound cards, network adapters, and storage devices (PCIe NVMe SSDs), and with the introduction of the new PCIe 5.0 standards, things got even more interesting.

On a motherboard, a PCIe slot comes in varying sizes, with x1, x4, x8, and x16, with x1 and x16 being the most common variations, and nowadays, the M. 2 slots are also common. The number in the slot signifies the number of lanes in a PCIe.

The bigger the number, the more lanes it has and the more bandwidth it can transfer. This is important to mention because, in practical situations, a big x16-looking slot could be an x1 slot, which you will find mostly in crypto-mining motherboards.

As we have seen in the past, each generation of PCIe is twice as fast as its predecessor and also backwards compatible. This simply means the latest generation of PCIe, which is PCIe5, is compatible with PCIe4, PCIe3, and more, but the speed and performance of the device will be limited. 

What Are PCIe Lanes?

Before we move forward, we need to know about PCIe lanes, and they come in two types: CPU lanes (connect directly to the CPU) and chipset lanes (connect to the CPU through the chipset). Chipset lanes have limited bandwidth, causing potential bottlenecks when multiple devices are connected. CPU lanes offer faster speeds and lower latency, especially for storage devices like NVMe SSDs.

In the past, using CPU lanes for storage meant sacrificing bandwidth for the GPU. However, with newer technologies like PCIe 4.0, this bottleneck is less of an issue, and now, with the introduction of PCIe Gen 5.0, this will not be much of an issue by a long shot.

PCIe 5.0: Do you need it?

PCIe 5.0 is the fifth generation of the Peripheral Component Interconnect Express (PCIe) interface, which was officially released in May 2019. It offers a maximum bandwidth of 32 GT/s, which in the real world translates to 64 gigabytes per second (GB/s) or 128 GB/s with PAM-4 encoding.

Compared to that, an x16-sized slot running at Gen 3 caps at around 16 gigabytes per second. Gen 4 gets 31.5 gigabytes per second. One fun fact about the new PCIe standard is that it achieves this extremely high speed of 32 GHz, which is six times faster than the CPUs that manage the data.

PCIe 4.0 vs. 5.0 With Gaming

For the majority of gamers today, PCIe 4.0 is more than sufficient, and upgrading to PCIe 5.0 specifically for gaming might not yield significant benefits immediately. The choice between PCIe 4.0 and 5.0 should be guided by considerations such as future-proofing, budget, and whether other components in the system (like ultra-fast SSDs or upcoming GPUs) can utilise the extra bandwidth provided by PCIe 5.0.

If you are building a new high-end system and want to maximise its lifespan and potential, opting for PCIe 5.0 could be a wise decision. However, for most current gaming needs, PCIe 4.0 remains very capable.

Which of PCIe 4.0 and 5.0 should you choose?

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RTX 4090 PCie 4.0 vs. 5.0

Now let’s address the elephant in the room and answer the question we’re all here for: Do you need PCIe 5.0 for your RTX 4090 right now? Absolutely not! But in the next two to three years, it will definitely be a yes!

You might be wondering why. At the time of writing, the current generation of fully maxed-out RTX4090 with 100% load only saturates 50 to 65% of the PCIe Gen 4 bandwidth, and the rest is just there, not being utilised at all. So, just having more bandwidth and transfer speeds will not make your games faster!

SSDs are a different case, though; there are some SSDs like the Crucial T700, the Firecuda 540 series, and the Aorus Gen5 10000, which is designed to work with the PCIe Gen 5.0 slot and has a theoretical maximum speed of 15.75 GB/s compared to 7.88 GB/s that we found on a PCIe Gen 4.0 slot.

While the interface itself can hit the speed I have just mentioned, some factors affect the real-world performance of a drive, like the SSD controller and the NAND Flash that is used to build the SSD. Also, pushing the controller to its maximum limit could introduce stability issues; there will also be thermal issues and much more that I could go on and on about! 

In simple terms, the benefits of the drive are not noticeable in everyday use. The reason for this is that the drive’s sequential speeds are much faster than what is needed for most tasks, and its random read and write speeds, which are more important for everyday use, are not significantly faster than those of Gen 4 drives.

However, the increased bandwidth of PCIe Gen 5 could be beneficial in the future, as it could allow for more lanes of PCIe connectivity. This means more devices can be connected to a computer without sacrificing performance. For example, you could connect 4 or 8 Gen 4 SSDs on a consumer platform, and you don’t need that enterprise solution that right now costs thousands of dollars. 

Another benefit of PCIe Gen 5 is when using “Direct Storage.” DirectStorage is a Microsoft API designed to significantly improve game loading times and overall performance by leveraging the speed and efficiency of NVMe SSDs. DirectStorage bypasses traditional storage bottlenecks by creating a more direct path between the game assets on the SSD and the graphics card’s memory (VRAM). It shifts the burden of decompressing game assets from the CPU to the more powerful GPU, freeing up CPU resources for other tasks and accelerating loading times. Game titles can significantly benefit from this.

Conclusion

Both the PCIe 5.0 and 4.0 platforms offer great flexibility and more than adequate choices of peripherals for your build, but with PCIe 5, you can rest assured that advanced SSDs and GPUs released in the next few years will be compatible with your system to the fullest. Additionally, a 20-lane CPU will provide a direct connection for the GPU and SSD, potentially reducing latency.

FAQ about PCIe 4.0 vs. 5.0