Hey there! As an tech enthusiast, you must have heard about the Peripheral Component Interconnect Express or PCIe interface being talked about often when dealing with latest generation hardware for gaming rig builds, graphics workstations and even enterprise servers.
In this extensive guide, I will walk you through everything important about the new PCIe 4.0 standard – how it compares to previous gen PCIe 3.0 across various metrics, where you can expect real-world performance gains, what new gear leverages PCIe 4.0, and perhaps most importantly, whether it makes sense for you to upgrade your own system!
What Does PCIe Do?
The PCI Express interface is used to connect devices like graphics cards, SSD storage and networking adapters to the CPU and motherboard chipset via high speed serial links or “lanes”. This communication system is critical for transferring large amounts of data quickly across the various subsystems.
Over the years, the capabilities and speeds supported by PCIe links has evolved rapidly to meet demands of emerging technologies. In fact, since the first PCIe 1.0 spec released in 2003, there has been a new version roughly every 3 years! Let’s quickly recap:
- PCIe 1.0 – Launched 2003
- PCIe 2.0 – Launched 2007
- PCIe 3.0 – Launched 2010
- PCIe 4.0 – Launched 2017
- PCIe 5.0 – Upcoming ~2023
So why does PCIe keep getting faster generations? Simply put, modern applications like 4K video production, data science workloads and immersive gaming require moving vast volumes of data very quickly – both from components to CPU, and back out to displays and networks.
PCI Express generational upgrades ensure your motherboard has the capacity to handle all this data movement using speedier links between attached devices and the CPU/chipset.
Now let’s see what specific enhancements PCIe 4.0 brings to the table…
PCIe 4.0 Upgrades and Enhancements
After PCIe 3.0 released in 2010, it took almost 7 years until PCIe 4.0 finalized in 2017. It ushers in a number of exciting upgrades:
Bandwidth and Transfer Rates
The flagship improvement is raw speed. PCIe 4.0 defines lanes with up to 16GT/s transfer rate, doubling PCIe 3.0’s 8GT/s limit.
This means significantly more data can move over the bus during a given time period. Here is a quick comparison:
| Spec | PCIe 3.0 | PCIe 4.0 | Increase |
|---|---|---|---|
| Max Bandwidth (x16) | 32GB/s | 64GB/s | 2x |
| Max Speed (per lane) | 8GT/s | 16GT/s | 2x |
As you can see, the doubling of per-lane transfer rate allows an equivalent doubling of total interface bandwidth capacity between the CPU and connected endpoints like your GPU.
Latency
PCIe 4.0 also halves the latency or delay between data requests and transfer completions to just 125 nanoseconds, down from PCIe 3.0’s 250ns.
While seeming tiny on paper, in the world of high speed computing, this sub 100ns latency gives a very noticeable boost for time-sensitive applications.
Power Efficiency
More speed generally requires more power. However PCIe 4.0 achieves its bandwidth doubling very efficiently – requiring only 4W per GB/s, less than half of PCIe 3.0’s 8W usage.
This improved energy savings is great news for gaming laptops, enterprise hardware and even environmental impact. Lower power costs also offset PCIe 4.0’s steeper hardware pricing.
No Physical Changes
Unlike previous version steps, PCIe 4.0 impressively retains full backwards compatibility for cables, connectors and sockets.
This means no replacing PCIe 3.0 add-in cards or running new cabling routes. As an end user you simply plug your upgraded GPU or SSD straight into existing PCIe slots to enjoy 4.0 speeds! (with supported motherboard and CPU of course!)
Real-World Performance Impact
Well those numbers and facts are nice, but what do they actually mean for YOUR experience? Does it make sense upgrading your personal rig or workstation to leverage PCIe 4.0?
The answer is a resounding YES for hardware buyers focused on maximum performance. Across nearly all modern computing workloads, PCIe 4.0 provides very tangible real-world speed improvements thanks to its added bandwidth headroom.
Let’s analyze some examples:
Gaming Frame Rates
For gaming and multimedia, graphics card upgrades reap major benefits from PCI Express 4.0.
High-end GPUs like NVIDIA’s flagship RTX 4090 demonstrate nearly 15% higher frame rates in many game titles running PCIe 4.0 compared to fallback 3.0 mode.
RTX 4090 PCIe 3.0 vs 4.0 gaming benchmarks [Source: TechPowerUp]
That’s the difference between smooth 60 FPS gameplay or stuttering just below 50 FPS on the latest titles using max graphics settings.
For competitive esports gamers, 4.0’s lower latency also provides snappier response times and quicker reaction ability.
Clearly gaming PCs should utilize PCIe 4.0 to avoid leaving easy performance on the table. But what about professional creative workflows?
Content Creation Speeds
For video production, 3D rendering and code compilation tasks, PCIe 4.0 accelerates transfer times for source data and final output products by around 25-50% over saturated PCI 3.0 links.
In fact creator-focused desktop workstations and laptops for animation, engineering and data science applications already recommend PCIe 4.0 compatible components to ensure fluid creative experience keeping users in their productive zone.
A great example is high speed NVME SSD scratch disks which see 4-5x speedup in large file transfer benchmarks on the PCIe 4.0 interface. For timeline-based video editing feeding high resolution footage, this makes a huge difference avoiding lag and skips.
Data Center Throughput
PCIe 4.0 advantages scale all the way up to enterprise server racks and cloud data centers thanks to improvements in multi-node communication and backend storage fabrics.
Leading hyper-scalers like AWS and Azure are qualifying next-gen server gear and interconnects to roll out improved service tiers leveraging PCIe 4.0. Particularly network-attached flash storage gets a large boost, now able to saturate many more PCIe lanes.
Industry projections estimate a potential 3-4x increase in SQL queries per second (QPS) for databases running on PCIe 4.0 storage backends relative to legacy PCIe 3.0 infrastructure still common in datacenters today.
Clearly the performance writing is on the wall when it comes to new PCI Express capabilities!
Latest PCIe 4.0 Hardware
Now that you’re excited about PCIe 4.0 performance, what kind of components and platforms actually support it today?
Let’s discuss some hardware bright spots taking advantage of the upgraded interface speed.
Samsung 980 Pro PCIe 4.0 NVMe SSD with heatsink [Image credit: IDG]
Graphics Cards
All current generation GPUs from both NVIDIA and AMD top out at PCIe 4.0 x16 connections. This includes offerings like:
- NVIDIA GeForce RTX 40 series
- AMD Radeon RX 7000 series
Interestingly, even previous gen flagships like RTX 3090 and RX 6900 XT cards demonstrated small but measurable performance gains when paired with PCIe 4.0 over default PCIe 3.0 mode.
Clearly graphics cards are now being designed from the ground up expecting PCIe 4.0 system connectivity.
Storage Drives
As mentioned earlier, bleeding edge NVMe solid state drives (SSDs) showcase the most drastic real-world speedups when upgrading from PCIe 3.0 to 4.0 slots.
Top tier Gen4 consumer drives like:
- Samsung 980 Pro
- WD Black SN850
- Seagate FireCuda 530
…consistently measure over 4x the sequential read/write throughput compared to prior gen PCIe 3.0 models, thanks to PCIe 4.0’s doubled interface bandwidth headroom.
For content production building up large local storage arrays, this class of SSD represents the perfect candidate to take advantage of the bandwidth benefits using PCIe 4.0 connectivity.
Network Cards
While Ethernet speeds topped out previously at PCIe 3.0 x4 (equivalent to ~4GB/s), cutting edge standards like 800Gb Ethernet are finally pushing into PCIe 4.0 territory.
In fact, bleeding edge 200Gb/s Infiniband HDR RDMA interfaces onboard servers already fully saturate a x16 PCIe 4.0 pipe thanks to ultra low latency requirements.
As networked computing gets snappier, purpose built network cards will be one of the next big peripheral classes to expect default PCIe 4.0 support going forward.
Upgrade Considerations for PCIe 4.0
Now before you rush off to install shiny new PCIe 4.0 hardware, it is worth pointing out that FULL platform readiness is required before you see any speed benefits.
While PCIe generations are generally backwards compatible for cables and card placement, the actual interface communication falls back to the slowest supported common speed across the chain.
Therefore to enable your speedy Gen4 GPU or SSD to stretch its legs, ensure ALL of the below components in your system support PCIe 4.0 communication:
- Processor – Must have PCIe 4.0 lanes from the CPU complexes
- Motherboard Platform – Requires updated chipset, BIOS and PCIe slot connections
- Operating System Driver – Full driver stack should support PCIe 4.0 handshake
Without end-to-end 4.0 readiness, dropping in a shiny new GPU won’t boost frame rates and risks leaving performance on the table!
While researching component specs, you may come across certain caveats around PCIe lane allocation and slot configurations for the above checklist. We won’t dive deeper here, but talk to your system integrator if building a production grade workstation or server rack.
As expected, costs are bit higher currently for the latest generation PCIe 4.0 hardware since the ecosystem is still ramping up. However knowing the tangible benefits, most enthusiasts find the 10-15% pricing premium very justifiable for future-proof performance.
Within another product cycle or two, PCIe 4.0 will become standard across all motherboard and component segments just like its predecessor generations.
What Does the Future Hold?
PCI Express technology continues its rapid innovation cadence in anticipation of next-generation computing requirements. In fact, active development and industry interoperability testing is already underway for PCIe 5.0!
PCIe 5.0 again doubles peak interface bandwidth to an incredible 128GB/s along with even better power efficiency. Expect to see initial PCIe 5.0 platforms and products demoed later this year, with volume rollouts in 2024.
Further out, the PCI-SIG has already reserved PCIe 6.0 branding for whatever comes next. If past trends are any indication, we could expect another 2x bandwidth multiplier to 256GB/s along with protocol and encoding optimizations. Exciting stuff!
While only bleeding-edge workstations and data center infrastructure may upgrade to PCIe 5.0 over next two years, it sets the technology foundation for future high performance computing needs.
The Bottom Line
There is no doubt PCI Express 4.0 accelerates interconnect speeds to the next level supporting modern bandwidth-hungry computing.
For gaming and professional media creation workflows, the measurable performance uplift is clearly worthwhile when coupled with high speed Gen4 hardware.
Although upgrading to PCIe 4.0 requires some investment, power users will find the real-world speed boosts incredibly beneficial for a smooth, future-proof experience. As high performance computing marches forward, PCIe slots will continue advancing at a rapid cadence for years to come.
I hope this guide offered you a helpful rundown explaining the new PCIe 4.0 capabilities! Let me know if you have any other questions.
