PCIe 4 vs. PCIe 3: Is It Time to Upgrade?
PCIe 3 has been available on a huge swathe of different motherboards since 2010, and continues to be the most populous PCIe port available in 2020. It 8217;s found on 300 and 400-series motherboards for AMD 8217;s first and second generation Ryzen CPUs, as well as on Intel 300-series boards used for its 8th and 9th-gen processors. It 8217;s also found on most boards released over a few years before these chip generations.
Motherboards may still technically support it, though, so it may be that when the next-next-generation Rocket Lake CPUs debut in 2021, that existing Comet Lake boards could gain the feature with a chip upgrade.
Other speculation says that Intel may skip PCIe 4 altogether and instead push for the recently standardized PCIe 5 with future CPU generations.
The greatest advantage of PCIe 4 over PCIe 3 is in its speed 8212; or overall bandwidth. Like generations of PCIe before it, PCIe 4 doubles its bandwidth over the last-generation, increasing the per-lane bandwidth to 2 gigabytes per second (2GBps). With options for 1x, 2x, 4x, 8x, and 16x slots, that increases the maximum potential bandwidth for a PCIe 4 slot to 64GBps.
Where this additional bandwidth can be taken advantage of in full is with other kinds of add-in cards. Most namely, storage. Multiple PCIexpress 4.0 NVMe drives can operate in RAID 0 configuration to offer sequential read/write speeds of up to 15GBps.
With little real-world tasks that can take advantage of the full bandwidth of PCIe 4 x16 slots, the major advantage of it, at least in the near future, will be in the reduction in lane requirements for devices and add-in cards. Instead of a 10 Gigabit network card requiring multiple PCIe 3 lanes, it can get away with just a 1x slot. Graphics cards can operate at PCIe 4 x8 speeds, enjoying the same bandwidth as PCIe 3 x16 slots, but with half the lanes used.
Those additional lanes can be freed up for additional devices in larger builds, or allow for faster devices to operate on smaller PCIe slots for more compact systems.
Supporting boards aren 8217;t limited to PCIe 4 devices either. PCIe 4 slots are entirely backwards compatible, meaning that any older-generation PCIe devices, whether it 8217;s first, second, or third generation, will work just fine with PCIe 4.标签：