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The long-awaited PCI Express 4.0 update is coming to a computer near you. At least, if you buy a new computer or update your system hardware, you can opt for the much faster PCIe 4.0 over the current 3.0 standard.
But what is PCIe 4.0? Will it help your system boot faster? Here’s what’s new with PCIe 4.0.
What Is PCIe?
The Peripheral Component Interconnect Express (PCIe) standard is a common motherboard connection. It allows various bits of system hardware to communicate with the motherboard and other parts of your system. Specifically, PCIe relates to system expansion cards, such as a graphics card (GPU), sound card, Wi-Fi card, or M.2 NVMe SSD.
As with most things, the higher the number, the faster the connection. PCIe 4.0 is the fourth iteration of the standard. Details of the PCIe 4.0 standard were published back in mid-2017. However, it has taken until now for any motherboard or chipset manufacturer to implement the new standard on upcoming hardware.
Your motherboard will have several PCIe slots. The PCIe slots come in several sizes: x1, x4, x8, and x16. The numbers detail how many “lanes” the PCIe slot has. More lanes equal a faster data connection. Most modern expansion cards work best in an x16 slot. That’s because it has the fastest data transfer rate. For instance, a modern GPU will use an x16 slot to transfer data rapidly to ensure you experience smooth and consistent gameplay.
One exception is for the M.2 form factor. M.2-based expansion cards are not compatible with the standard PCIe lane layout. Instead, M.2 expansion cards use PCI Express M.2 connections with either two or four lanes. PCIe M.2 replaces the older mSATA standard.
Is PCIe 4.0 Faster?
Yes, PCIe 4 is faster than the previous generation, PCIe 3. It is almost twice as fast, doubling the data transfer rate to 16 gigatransfers per second (G/Ts). However, G/Ts aren’t a very useful data transfer metric for the vast majority of people, including myself.
In more useful terms, an x16 PCIe 4.0 slot (the largest slot) has a one-way data transfer of up to 32GB/s. That means you can have a maximum of 64GB/s flowing in both directions. However, using the higher amount of 64GB/s is slightly disingenuous, because you don’t achieve that rate in a single direction.
Still, 32GB/s is a significant improvement on PCIe 3.0, which tops out at around 16GB/s.
Which Hardware Does PCIe 4.0 Speed Up?
Certain bits of hardware will receive a greater PCIe 4.0 performance boost than others. PCIe updates affect your system expansion cards, such as Wi-Fi, Ethernet, and graphics card. However, an update doesn’t always deliver an immediate boost. Why? Well, some of your system hardware is already operating at capacity.
Take your graphics cards. The idea of boosting its capabilities is great, right? Well, unless you’re gaming at a resolution of 3840×2160 with a refresh rate of 144Hz, you’re not even topping out the current PCIe 3.0 standard. Research by Intel into the Gaming Impact of PCIe 4.0 shows that current hardware still has a performance gap before maxing out the current standard. Check out the following table, which details the data bandwidth of various resolutions:
The biggest immediate performance gains for PCIe 4.0 come in your system storage. Corsair’s Force Series MP600 M.2 SSD supports PCIe 4.0 and with that, data transfer rates of up to 5GB/s—that’s fast! Something you might note about the Corsair MP600 is the enormous heatsink. You have to assume that a significant increase in temperature accompanies the PCIe 4.0 speed boost, so that is something else to bear in mind.
Can I Buy Hardware That Uses PCIe 4.0?
The introduction of new hardware supporting PCIe 4.0 is what is catching the eyes of businesses and consumers alike.
AMD X570 Chipset
AMD’s Ryzen CPU series continues to use the same processor socket: AM4. Your Ryzen CPU is interchangeable for any motherboard with an AM4 socket, no matter the Ryzen CPU generation. The difference now for AMD CPU owners is that if you want to make use of the faster PCIe 4.0 standard, you need a new motherboard built to the new standard.
The new AMD X570 chipset will support PCIe 4.0 out of box. Before the announcement, dribs and drabs of updates were adding PCIe 4.0 support to some AMD motherboards, primarily higher spec X470 and X370 models). But because of the demands of the PCIe 4.0 standard, retrospective updates aren’t possible for every chipset. Hence, AMD will no longer issue PCIe 4.0 updates for existing chipsets.
AMD’s senior technical marketing manager, Robert Hallock, explained the decision in a Reddit post.
“This is an error we are correcting. Pre-X570 boards will not support PCIe Gen 4. There’s no guarantee that older motherboards can reliably run the more stringent signaling requirements of Gen4, and we simply cannot have a mix of “yes, no, maybe” in the market for all the older motherboards. The potential for confusion is too high. When final BIOSes are released for 3rd Gen Ryzen (AGESA 1000+), Gen4 will not be an option anymore. We wish we could’ve enabled this backwards, but the risk is too great.”
Elsewhere, you can buy system storage prepped for PCIe 4.0. At Computex 2019, a global computer development conference, Gigabyte announced an obscene 8TB PCIe 4.0 SSD. Technically four 2TB SSDs woven into a single GPU-style expansion card, the drive has a staggering 15,000MB/s read and write rate.
If that sounds a little like overkill, Gigabyte also launched the AORUS NVMe Gen4 SSD. The AORUS NVMe Gen4 SSD hits around 5,000MB/s read speed, and 4,400MB/s write speed. The AORUS comes in 1TB or 2TB sizes.
Not sure what’s best for you? Check our guide to PCIe vs. SATA SSDs.
When Is PCIe 5.0 Coming?
Funny you should ask that.
Just as PCIe 4.0 begins gathering speed and people are already looking forward to PCIe 5.0. That’s because the PCI Special Interest Group (PCI-SIG), the developers of the PCIe standard, announced PCIe 5.0 soon after PCIe devices finally hit the market. The finalized PCIe 4.0 specifications are arriving a couple of years behind schedule, causing some overlap between the two.
PCIe 5.0 will double the data transfer bandwidth again. That means an increase to 32G/Ts, or a one-way transfer rate up to 64GB/s.
Should You Upgrade to PCIe 4.0 Hardware?
The difficulty here lies with knowing where computer hardware is heading. The PCIe 4.0 reception is underwhelming, to say the least. That’s likely due to the fact most hardware isn’t making best use of the existing PCIe 3.0 standard, plus the knowledge that within the next two to five years, PCIe 5.0 will begin entering hardware production.
In that, the delay to PCIe 4.0 creates a difficult situation. If you were already going to upgrade and have the money to spend, considering PCIe 4.0 is worthwhile. If you’re mid-cycle, or just looking at a speculative upgrade, perhaps wait until more is known about the timeframe for PCIe 5.0.