As a tech enthusiast building my new gaming PC, I face an important question – should I upgrade the old PCI slots and cards in my current system to the newer PCI Express standard?
To help decide, I did a deep dive into exactly what PCI and PCIe are, what‘s changed over the years, and whether its worth the upgrade. In this 4-part guide, I break down my learnings to upgrade my setup and maximize performance!
A Brief History of PCI and PCI Express
First, some background. The Peripheral Component Interconnect, aka PCI, arrived way back in 1990 from Intel‘s architecture labs. At the time, ISA and MCA slots were common but bottlenecks for storage and graphics cards.
Intel‘s new parallel bus standard delivered a much-needed speed boost, hitting speeds up to 133MB/s. This fueled rapid adoption through the 90s and early 2000s across all types of desktop PCs and servers.
But by the early 2000s, even PCI couldn‘t catch up to faster CPUs and surrounding tech improvements. This kickstarted development of the PCI Express (PCIe) standard to replace PCI.
After evaluating "High-Speed Interconnect" and "3GIO" names, the final PCIe 1.0 specification was unleashed in 2003 by the PCI Special Interest Group (more later). Some key evolutionary milestones:
2003 – PCI Express 1.0 debuts, provides 2.5GT/s speeds
2007 – PCIe 2.0 arrives, doubles throughput to 5GT/s
2017 – PCIe 4.0 hits 16GT/s, 8X faster than PCI
Today PCIe host interfaces exceed 32GT/s bandwidth with support for cutting edge peripherals. The legacy PCI standard remains usable but obsolete for modern gaming and graphics needs.
Comparing PCI and PCIe Specifications
Both PCI and PCI Express provide a physical interface to plug-in components like WiFi cards, GPUs, NVMe SSD drives etc. into a motherboard. But under the hood, they operate quite differently!
Key Differences
Parallel vs Serial
The PCI data bus uses parallel communication. Think of it like a multi-lane highway where cars (data bits) move side-by-side across individual lanes simultaneously. More lanes equals more throughput.
In contrast, PCI Express serialized everything into a single lane. Here cars follow one another sequentially like a train. This eliminates timing and coordination across lanes.
Parallel Pros – Simple synchronization across lanes. More resilience to interference
Serial Pros – Minimizes traces, pins, components. Higher native speeds as technology progressed
Given production cost and speed advantages, PCIe fully adopted serial pipeline communication.
Physical Slot Types
My current PC only has the one legacy PCI connector type – a standardized 32 or 64-bit slot. It accepts any PCI card but nothing else.
PCIe connectors however come in flavors like M.2, U.2, mini sizes to accommodate smaller form factors and devices. There‘s a lot more physical versatility to account for specialized or compact addons.
Speed and Bandwidth
This is the game changing difference most important for upgrading aging slots! Check out max theoretical transfer rates between the two:
| Spec | PCI | PCIe 1.0 | PCIe 2.0 | PCIe 4.0 |
|---|---|---|---|---|
| Released | 1990 | 2003 | 2007 | 2017 |
| Bandwidth | 132MB/s | 250MB/s | 500MB/s | 16,000MB/s |
| Data Rate | 133MHz | 2.5GHz | 5GHz | 16GHz |
As you can see, early PCIe was already faster than PCI – first-gen delivered nearly 2X the throughput! Each generation then roughly doubled the bandwidth exponentially.
Today a PCIe 4.0 slot can push over 7,000X more data per second than 1990s PCI technology – massive for speed junkies like me! The "Express" name is fitting 🙂
And we‘re already seeing compatible PCIe 5.0 components too. Exciting times ahead to leverage these interface advancements!
Let‘s now move onto real-world usage and applications taking advantage of PCI Express capabilities today:
Modern Applications of PCI Express
Here are just some examples of cutting-edge PCIe tech found in modern computers:
Discrete Graphics Cards
Gaming GPUs have huge appetites – PCIe 4.0 x16 slots can drive frame buffers up to 32GB and deliver over 15GB/s per direction to the card. Plenty of pipeline for smooth, rich graphics and video.
Nvidia even created a multi-card SLI bridge using PCIe. With 20 PCIe lanes between two cards, it syncs frames data at over 20GB/s for seamless multi-monitor gaming or video production.
NVMe Solid State Drives
These bleeding-edge SSDs need performance to match latest PCIe CPU chipsets and Thunderbolt 3 interfaces. Leveraging 4 PCI 3.0 or PCIe 4.0 lanes provides up to nearly 4GB/s reads and writes – 10X+ faster than SATA SSDs.
All that bandwidth translates to lighting quick transfer of multi-gigabyte videos, game installs or bootups measured in seconds rather than minutes.
USB/Ethernet Controllers
High throughput BUSes like Thunderbolt 3 offer another way to utilize PCIe externally. Intel‘s Falcon Ridge controller uses PCIe 3.0 x2 lanes, providing enough bandwidth for dual 4K displays AND external GPUs!
This daisy chaining of desktop capabilities and docking station convenience requires PCIe underneath. Exciting to consider as an external upgrade path too.
AI and GPGPU Accelerators
An emerging trend is dedicated PCIe accelerator cards for artificial intelligence, machine learning and other highly parallel workloads. These specialized processors crunch teraFLOPS leveraging 16 or more PCIe 4.0 lanes tapping directly into GPU memory and caches.
Nvidia‘s Tesla T4 for data centers packs 520 TeraOps of power! Frees up CPU cycles better spent elsewhere while enjoying speedy PCIe interconnect.
Audio Production
For professional studio audio recording or home enthusiasts, PCIe soundcards provide extremely low latency monitoring and routing capabilities. Music gear company Focusrite offers acclaimed PCIe audio interfaces with rich A/D conversion, DSP powered mixes and more.
Reduced lag allows artists to layer tracks and apply real-time effects without delay or distraction through high-performance PCIe connectivity.
As you can see, PCI Express enables some seriously cutting-edge use cases! Makes me excited to upgrade and tap into all this performance potential.
The PCI Special Interest Group
Driving further innovation is the PCI Special Interest Group (PCI-SIG) – a non-profit consortium founded back in 1992 when PCI was gaining ground. Today, over 800 industry leaders participate including Dell, AMD, Nvidia, Apple and many more.
Think of them like a standards body who meet regularly to evolve PCI specifications. Adoption of PCI-SIG blessed revisions is voluntary but strongly recommended for interoperability. Vendors leverage published specs to build compatible products and drivers.
Member meetups also provide early access to next-gen tech like PCIe 5.0 in development. Exciting to see collaboration accelerating advancement!
Conclusion – Yes, Upgrade to PCIe!
Given everything learned researching PCI vs PCI Express advancements over the years, I‘m absolutely upgrading my desktop!
While PCI served us well until early 2000s, the performance, versatility and future-proofing that PCIe 4.0+ offers is on another level entirely.
All the latest GPUs, NVMe drives and accessories rely on PCI Express spec‘s speed and capabilities today. And with support growing for 5.0, 6.0 down the road, it will carry us even further.
My new build will take full advantage with a Z690 motherboard, PCIe 4 SSDs, latest Intel chipset and premium graphics card. Time to give this old gear an overdue PCIe transformation!
I hope you found this PCI vs PCIe comparison helpful. Let me know if you have any other questions on upgrading your desktop or server. Happy to chat more!
