PCIe4.0
PCWorld|July 2019

EVERYTHING YOU NEED TO KNOW, FROM CAVEATS TO COMPATIBILITY TO SPECS

AMD’S NEW RYZEN PLATFORM USHERS IN THE FIRST BIG CHANGES TO PCIE SINCE 2010.

Gordon Mah Ung

Come July, AMD gets to hoist the trophy in the race to the next-generation PCIe 4.0 interface for desktop PCs. By combining its upcoming Ryzen 3000 CPUs, Radeon RX 5700 graphics, X570 chipset, and a new spate of PCIe 4.0 SSDs, consumers will be able to build or buy the first PCIe 4.0-based PC.

PCIe 4.0 sounds exciting—it’s the first big change to the interface since 2010. But as always, the questions of who can get it (and who can’t), and who really needs it, are more nuanced than you’d think. Keep reading to get the all the details.

WHAT IS PCIE 4.0?

PCIe 4.0 is the next iteration of the PCIe interface. It’s used for connecting add-in cards and M.2 drives, as well as interconnecting various chips inside a PC. Compared to its predecessor PCIe 3.0, PCIe 4.0 essentially doubles the overall throughput. The chart below from PCI-SIG lays it all out nicely:

If that looks like a boatload of bandwidth, it is. Seizing an opportunity to troll Intel and Nvidia, AMD ran Futuremark’s unreleased PCIe feature test to show how a Ryzen 7 3800X coupled with a Radeon RX 5700 in PCIe 4.0 mode offered 69 percent more PCIe throughput performance than a Core i9-9900K and GeForce RTX 2080 Ti.

REALITY VS. HYPE

One problem with AMD’s demonstration, however, is that “69 percent” performance, while most likely real, probably doesn’t actually translate into more practical gaming performance today. That’s because few games ever saturate the 32GBps of data today’s x16 PCIe 3.0 slot can carry.

This disparity between demand and supply has been proven out many times over the years. Alienware’s laptops actually limit the slot to x8 PCIe 3.0, siphoning off the rest to support the external graphics port. The reason? It doesn’t matter (much).

STORAGE

PCIe promises a huge boost in other areas of the PC, though. The most obvious one is storage, where AMD also demonstrated the performance difference using SSDs.

We witnessed a single Gigabyte Aorus M.2 PCIe 4.0 SSD hitting 5GBps reads and 4.3GBps write speeds. That’s about 35 percent higher sequential performance than we’ve seen from some of the faster M.2 PCIe 3.0 SSDs.

It gets even crazier if you run them in RAID 0, which is what Gigabyte did using a PCIe 4.0 add-in card holding four 2TB PCIe 4.0 M.2 SSDs. You can see the card below with its shroud off. The card is essentially one big passive PCIe extender.

Continue reading your story on the app

Continue reading your story in the magazine

MORE STORIES FROM PCWORLDView All

What to look for in a gaming monitor: The specs that matter

Gaming monitors are awesome, but which one is right for you? Let us guide you through the specs you should care about.

10 mins read
PCWorld
January 2021

WD Black SN850 NVMe SSD: Fantastic sustained write speeds via PCIe 4.0

This new PCIe 4 NVMe SSD is like-priced and about as fast as its mighty Samsung rival.

3 mins read
PCWorld
January 2021

Tested: 5 things you need to know about AMD's Radeon RX 6900 XT

Don’t have time to sift through benchmarking charts? Read this instead.

6 mins read
PCWorld
January 2021

Xbox Game Pass Ultimate tip: How to get 3 years of access to hundreds of games for dirt cheap

This incredible deal is still possible, but who knows how long it’ll stick around.

6 mins read
PCWorld
January 2021

How DirectX 12 Ultimate supercharges graphics on Windows PCs and Xbox

DirectX 12 Ultimate serves as a force multiplier for the entire gaming ecosystem.

7 mins read
PCWorld
January 2021

8 ways to make Cyberpunk 2077 run faster

Put the pedal to the metal, choom.

8 mins read
PCWorld
January 2021

Zenfox T3 3CH Dash Cam: Three cameras give you more to like

It provides good front, interior, and rear coverage, but its bulk could pose some installation issues.

4 mins read
PCWorld
January 2021

Acer Swift 5 (2020) : This MacBook Air alternative plays Fortnite

At 2.3 pounds, the Acer Swift 5 is a tiny Tiger Lake powerhouse.

8 mins read
PCWorld
January 2021

The Porsche Design Acer Book RS brings sports-car flair to the laptop

With a name like that, it has a reputation to uphold.

3 mins read
PCWorld
December 2020

THE BEST GAMES of this GENERATION

THE END OF A CONSOLE GENERATION IS ALSO THE PERFECT TIME FOR A RETROSPECTIVE.

10+ mins read
PCWorld
December 2020