PCIe 3.0 vs 4.0: What’s the Difference and Which Is Better

PCIe 3.0 Vs PCle 4.0: Which is better?

PCle has been people’s choice for connecting their high-speed peripheral devices for the past decade. Still, people are looking for better and faster ways to connect their devices which is why manufacturers are continuously launching new and better versions of PCle.

Among all versions, PCle 3.0 and PCle 4.0 have got the most attention among consumers. If you’re reading this article, you are probably experiencing that PCle 3.0 and PCle 4.0 are the latest trends in technology. But what are the differences between the both? Well, this article has the answer. 

Before we dive into the comparison, let’s first see what a PCle is and PCIe 3.0 vs 4.0.

What is PCle

PCIe (Peripheral Component Interconnect Express) is a speed interface standard for a high-speed connection between a computer’s motherboard and other peripherals.

Every desktop Pc has several PCle slots on the motherboard to which you can attach graphic cards, Hard drives, Wi-fi, SSDs, Ethernet Hardware, and RAID cards.

PCle slots have different configurations, such as X1, X4, X16, and X32. A configuration of X1 means that the PCle slot has one lane and can transfer one bit of data per cycle. In the case of X4, PCle has four lanes and can transfer four bits of data per cycle.

The market has seen many new versions of PCle after the first version (PCIe 1.0) in 2003, such as PCIe 2.0, PCIe 3.0, PCIe 4.0, and PCIe 5.0.

These versions are the upgraded and improved versions of their previous model. Of all these versions, the PCle 3.0 and PCle 4.0 have gotten the most fame, which is why they are often compared.

What is PCIe 3.0

PCle 3.0 was released in November 2010 with an 8 GT/s transfer rate. It provided faster signal speed with a lower data transmission delay than its earlier versions. It had both backward and forward compatibility.

For example, a PCIe 3.0 SSD can be inserted into a PCIe 4.0 slot of a motherboard with the Gen 3 slot’s bandwidth and a motherboard with a Gen 2 slot.

Besides this, PCIe 3.0 optimizes enhanced signaling and data integrity, including equalization, transmitter and receiver channel enhancements, and clock data recovery.

PCIe 3.0

What is PCIe 4.0

PCIe 4.0 came into the market on June 8, 2017, with twice the bandwidth offered by PCIe 3.0. The 16 GT/s connection rate offered by PCle 4 brought OCuLink-2, an excellent alternative to Thunderbolt.

Like PCle 3.0, it also has backward and forward compatibility for software and uses a mechanical interface. Plus, it also showed improvement in terms of scalability, flexibility, and lower power.

X570 chipset of AMD and NVMe PCIe 4.0 SSD by NETINT Technologies feature the same specs as the PCle 4.0.

PCIe 4.0

PCIe 3.0 vs 4.0

We can compare PCle 3.0 with PCle 4.0 in four main areas: Slots, Speed, Compatibility, and Price. So let’s dive into the comparison.


The PCIe slots play a significant role in the performance and compatibility of the PCle. Therefore, it should be the first thing you consider before purchasing a PCIe. 

The slots vary in length and speed depending on the number of PCIe lanes on the motherboard. Since each lane has an independent connection between the PCle controller of the motherboard and the expansion card, the number of lanes impacts the bandwidth scales.

Each lane has two pairs of wires, one for receiving and the other for transmitting. 

As mentioned above, PCle slots come with different lanes, such as X1, X4, X16, and X32. For example, the PCle 3.0 X4 is a Gen 3 expansion card or slot with a four-lane configuration.

PCle slots

PCIe 3.0 and 4.0 slots have a lane configuration of X1, X2, X4, X8, and X16, but the transfer rate per lane and bandwidth throughput differ. The PCIe 3.0 slot has a transfer rate of 8 GT/s per lane, while a PCIe 4.0 slot has a 16 GT/s transfer rate per lane.

The bandwidth depends on the lane configuration as PCIe 4.0 X4 has a bandwidth of 7.877 GB/s while the PCIe 3.0 X4 has a bandwidth of 3.938 GB/s, which is almost half of the PCle 4.0 X4.

Even though the PCle is 4.0 is better than 3.0 based on the things discussed above; it is better to purchase a PCle 3.0 if your motherboard has PCle 3.0 slots.


Though PCIe 3.0 and PCIe 4.0 are both backward and forward compatible, the peripheral devices that use the PCIe slots to connect with the motherboard perform differently with different sized PCIe lane configurations.

PCIe 3.0 SSD card can be inserted into a motherboard with PCIe 4.0 slots, although it wouldn’t be able to utilize the higher bandwidth of the Gen 4 slot fully.

However, you need to be sure that the motherboard has at least an equal, if not greater, several lanes than the expansion card inserted; otherwise, you can’t physically insert the card into the slot.

PCle compatibility

For example, if you have a PCle 3.0 X8 SSD, you can insert it into a PCle 4.0 X16 or X8 slot; but you can’t insert the same in an X2 or X4 slot. So before purchasing a card, always check the number of lanes you have on your motherboard.


Speed is also a very crucial factor when it comes to comparison between PCle 3.0 and PCle 4.0.

As discussed above, PCle 3.0 has a transfer speed of 8 GT/s, while PCle 4.0 has a transfer rate of 16 GT/s. Therefore it wouldn’t be wrong to say that PCle 4.0 has twice the speed of PCle 3.0.

The speed of the PCle also varies based on the different lane configurations, as more lanes mean more bandwidth. For example, PCle 4.0 X1 has a transfer speed of 2GB/s, while PCle 4.0 X16 has a transfer speed of 32 GB/s.

In contrast, PCle 3.0 X1 has a transfer rate of 1GB/s, and PCle 3.0 X16 provides 16GB/s of transfer speed.

PCle Speed

So without a doubt, the PCle 4.0 is twice as better as PCle 3.0 when it comes to speed.

Note: The data transfer speed of PCle 3.0 and PCle 4.0 may also differ depending on factors like motherboard slots and manufacturers.


There is a significant price difference between PCle 3.0 and PCle 4.0 even if the manufacturer, lane configurations, storage capacity, and interface are the same. For example, buying a Samsung 1TB NVMe PCIe 3.0 x4 internal SSD will cost around $120, but if you go for a Samsung NVMe 1TB PCIe 4.0 x4 SSD, it will cost you $185$.

PCIe Gen 3.0 Vs. 4.0 in Gaming

For gaming, you don’t need the PCle 4.0 yet, as even the most modern GPUs cannot fully utilize the PCI 3.0 bandwidth. Even if you use a PCle 4.0, the difference it makes isn’t big enough to be considered. 

However, a few years ago, a german website tested RX 5500 XT with PCle 3.0 and found that it limited the performance of RX 5500 XT. When they tried PCle 4.0 with it, they found that the GPU performed much better. 

This was because the PX 5500 XT only had 4GB VRAM, and when the storage was fully occupied, the data got stored in the RAM. As the PCle has a faster read and write speed, it significantly improves the performance of GPU that have 4GB or Lower VRAM. 

But it would help if you remembered that this problem was only limited to AMD. Also, the RX 5500 XT is a budget card, and it would be better to invest in a better graphic card than installing it in a PCle 4.0.

In the case of Mid and High-end GPUs, you don’t need to worry about the PCle 3.0 slowing down your performance. Even a high-end GPU like RTX 2080 Ti barely max out the bandwidth of PCle 3.0 X8. If you have a PCle 3.0 X16, you will only see a single digit of performance improvement. 

PCIe Gen 3.0 Vs. 4.0 for Professional Use

A high data transfer rate is crucial for programmers and Computer science engineers as they have to train and test machines and learn algorithms that must be stored and fetched repeatedly. A high transfer rate is also necessary for performing complex simulations and using real-time applications.

PCle 4.0 has twice the speed of PCle 3.0, so it’s a better choice for professionals. The amount of work PCle 3.0 can do with eight slots is equal to the amount of work PCle 4.0 can do with only four slots having four slots to spare. The spare slot can thus be used to connect other devices.

However, no speed is good enough for professional use, and there is always a need for faster speed. So even though PCle 4.0 is faster than PCle 3.0, there are still faster ones in the market, like PCle 5.0 and PCle 6.0. Therefore if you have enough budget and looking for something for professional use, you should go with the latest one.


There is no doubt that PCle 4.0 is better than PCle 3.0. However, in some situations choosing PCle 4.0 over PCle 3.0 won’t make much difference. Such as, in gaming, when you can’t fully utilize the PCle 3.0, what’s the point in spending more to buy a PCle 4.0 when it wouldn’t even make a considerable difference? 

If you’re seeking a PCle for professional use, you should go for the PCle 4.0 if you don’t have the budget to buy the latest PCle 5.0 or PCle 6.0.

However, no matter which one you buy, ensure that your motherboard’s slot and lane configurations support that PCIe version beforehand.

Meet the Author

Abdul Rahim has been working in Information Technology for over two decades. Learn how Abdul got his start as a Tech Blogger , and why he decided to start this Software blog. If you want to send Abdul a quick message, then visit his contact page here.