90 PCWorld JULY 2019FEATURE PCIE 4.0: EVERY THING YOU NEED TO KNOW
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).C
ome 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:AMD’s demo featured Futuremark’s new PCIe feature test. It showed a PCIe 4.0-based Radeon RX 5700
besting a PCIe 3.0 GeForce RTX 2080 Ti in transfer performance.