What is PCIe 4.0 and how will it affect my new build?
Once upon a time there was a quaint little slot on your motherboard called the Advanced Graphics Port or AGP for short. The AGP port was specially designed to enable you to get the most out of your then modern graphics cards so that you could get amazing framerates and performance playing such amazing games as Unreal. Then along came the PCIe or Peripheral Component Interconnect Express slot, which made AGP redundant by 2005 and extinct by 2010.
These little slots on your motherboard use “PCI Lanes” for interconnectivity between your CPU, motherboard, and devices. Consider it the backbone of all communication throughout your PC. The faster the interface, the faster the components they support. Each slot is allocated up to 16 lanes, typically referred to as x16.
So why is this important to you? Nvidia just released the new 30 Series cards, including the much sought after 3080 RTX. One of the most popular questions is whether or not running the graphics card on PCIe 3.0 will cause any performance issues over PCIe 4.0. The performance is very similar, however, you can get away with the same performance at x8 on PCIe 4.0 which would match the x16 performance on PCIe 3.0. Most mainstream processors and systems only allocate 24 total lanes for PCIe connectivity. Your graphics card wants to eat up 16 lanes (x16). If you use an M.2 storage drive, it wants to eat up 4 lanes (x4). That leaves you with a remaining 4 lanes for other devices before your graphics card is forced to run on 8 lanes (x8) so that the interconnectivity can be used for other devices like additional M.2 drives, PCIe expansion cards, video capture cards, etc.
The question shouldn’t be “will my 3080 work on PCIe 3?” your question should be “how is PCIe 3 limiting the performance of my other devices?”. Intel’s flagship processor, the 10900K, only supports PCIe 3.0 which means that the x4 speed available to an M.2 storage drive maxes out at 3,938MB/s. PCIe 4.0, supported by the most recent AMD chipsets, maxes out at 7,877MB/s. Which at double the performance, is quite substantial.
Again you may be asking, but why is this important? One of the major notes that I took away from the Nvidia 30 series launch, which was far more interesting than the launch itself, was the announcement of Microsoft DirectStorage. DirectStorage in a nutshell will enable direct streaming of data and game assets from your modern NVMe M.2 drive directly to the GPU with far more efficiency than current standards will allow.
The most recent M.2 drive from Samsung, the 980 Pro, has blazing fast read speeds up to 7,000MB/s. If you are on a platform with PCIe 3.0 you cannot go faster than 3,938MB/s regardless of how fast the drive you purchased is. Even PCIe 4.0, the fastest technology available to modern consumers, cannot support drives faster than 7,877MB/s. When the time comes for Microsoft to enable DirectStorage between your Nvidia RTX cards and your NVMe storage drives you are going to want to be able to take advantage of that.
Arguably modern video game titles won’t be making use of the technology. For a couple of years there may be some games like CyberPunk 2077 that just might implement it post-launch just to explore what they can do. This new method of accessing data will revolutionize load times in games and allow for bigger and more advanced games to be developed and push the limits of our current technology even further.
To make matters even more complicated, PCIe 5.0 is just around the corner and can be expected as early as late 2021 or as delayed as late 2022. PCIe 6.0 is already in development and already being planned and we could see it as early as late 2022 or as delayed as late 2024 in consumer products.
So what should you do? Should you go out and purchase a brand new PCIe 4.0 platform to take maximum advantage of new NVMe storage and push the limits of your new 3080 RTX graphics card? Or, should you wait for 2022 and jump into PCIe 5.0 which will be double the bandwidth of PCIe 4.0?
It’s up to you! The answer is really a matter of personal choice. The truth is that the prospects of where technology is going and the possibilities of what it may unlock in the near future is very exciting!
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