Have you peeked inside your computer lately? If it‘s a relatively modern system, you‘ll likely spot those ubiquitous PCI Express (PCIe) slots and connectors that power all our latest devices and upgrades.
But not that long ago, the now antiquated PCI standard dominated internal computer expansion. First introduced in 1990, PCI sticks around today – barely.
So what is this PCIe technology that‘s taken over? As an experienced tech specialist, let me walk you through a detailed yet easy-to-understand comparison of the PCI vs PCIe standards.
I‘ll demystify exactly how and why newer PCIe became the undisputed champion for connecting devices to your motherboard.
What Are PCI and PCIe? A Quick History
Back in the early days of home computing, adding new functionality like sound cards, TV tuners, and disk drives involved complicated installations and configurations.
The Peripheral Component Interconnect standard – what we call PCI – changed all that. Released by Intel in 1990, PCI provided a plug-and-play interface that allowed easy installation of expansion cards inside PCs.
PCI delivered a parallel communication interface and dedicated slots for add-in cards. This drove an explosion of innovation throughout the 1990s. Graphics cards, modems, extra USB ports – you name it. The PCI standard and universal card shape ensured compatibility across manufacturers.
By 1999, over 1 billion PCI devices populated computers around the world. But with rapidly advancing CPU and technology speeds, it soon became apparent PCI lacked the bandwidth future computing innovations would require.
Enter PCI Express, first launched in 2003 (under the name 3GIO). Providing over 10 times the bandwidth of PCI thanks to a new serial interface and speedy connector lanes, PCIe ensured support for coming advances in storage, graphics, networking and more.
Although PCIe 1.0 debuted at just 250 MB/s, each new generation delivered exponential improvements:
- PCIe 2.0 (2007) – 500 MB/s
- PCIe 3.0 (2010) – 1 GB/s
- PCIe 4.0 (2017) – ~2 GB/s
- PCIe 5.0 (2019) – ~4 GB/s
- PCIe 6.0 (2021) – ~8 GB/s
Today PCIe dominates modern computing, serving over 80% of the PC internal expansion market. So what changed to allow PCIe to so decisively move beyond PCI?
4 Key Advantages PCIe Holds Over PCI
PCI paved the way for an explosion of computer add-ins during the ‘90s. Yet as computing entered the 21st century, next-gen devices needed far more capable interfaces.
Here are 4 core advantages the newer PCI Express holds over legacy PCI:
1. Blazing Fast Serial Interface
The parallel communication architecture of PCI worked well in early PCs. But transmitting large blocks of data simultaneously introduces complex timing challenges. And parallel data links consume space routing multiple channels across a motherboard.
PCIe utilizes speedy serial data transfer instead. Its simplified lane architecture serially transmits data packets over fewer traces, while clocking occurs separately alongside. This allows far faster transfers with less overhead.
Real-world impact? Huge. Achieving only 133 MB/s max, PCI‘s lack of bandwidth throttles contemporary GPUs, SSDs and other add-ins. PCIe‘s 32 GB/s (and growing!) capably handles anything you throw at it.
2. Backward Compatibility
PCI Express smartly incorporated backward compatibility with PCI right from the 1.0 release in 2003. This ensured a smooth transition for legacy PCI peripherals during the PCIe migration.
This cross-compatibility delivers flexibility. An old PCI WiFi card won‘t achieve cutting-edge speeds in a modern PCIe system. But it‘ll likely still function just fine for light web browsing and email.
3. Scalable & Flexible Physical Specification
Unlike PCI slots which always supported a single connector size, the PCIe physical form factor scales to match device requirements. Available in x1, x4, x8 and x16 lane configurations, each sequentially doubles available bandwidth.
This makes PCIe well suited for anything from modest x1 sound cards to graphically intense x16 GPUs. Additional form factors like M.2 and U.2 compactly support SSDs and enterprise hardware.
4. Excellent Transmission Reliability
Higher data rates introduce risks – electromagnetic noise can corrupt signals, manufacturing defects crop up. So the PCI SIG implemented robust error detection, reporting and handling capabilities into PCI Express.
Features like automatic retry, advanced signal integrity, and traffic class prioritization delivers near perfect data transmission. That‘s crucial for GPUs streaming massive textures or PCIe SSDs reading/writing terabytes annually.
PCIe Dominates Modern Computer Expansion
Thanks to these technical advantages over PCI, PCI Express has become the interface of choice for contemporary computer motherboards and high-speed devices.
Here are some of the most prominent ways PCIe appears in modern PCs:
- Discrete Graphics Cards: High-end GPUs connect via x16 PCIe slots, with 500+ watt monsters like AMD’s RX 6900 XT requiring PCIe 4.0’s 32 GB/s for smooth 160+ FPS gaming.
- SSD Storage: Blazing PCIe 4.0 and 5.0 M.2 SSD drives saturate older SATA and PCI buses. Leading Samsung and WD models exceed 6,000 MB/s read speeds!
- WiFi and LAN: Onboard WiFi often connects via PCIe x1, with premium LAN cards using x4, x8 or even x16.
- USB/Thunderbolt Controllers: Built into motherboards, these connect via PCIe lanes to the chipset.
- Audio Cards: Sound cards typically occupy x1 PCIe or USB ports.
Moving On From PCI – Making the Leap to PCIe
I think it’s quite clear PCI Express offers substantial benefits over the now dated PCI standard. Backward compatibility means you needn‘t rush out upgrading existing PCI gear.
But if shopping for new components, PCIe undoubtedly paves the way to maximize performance. With each successive generation stretching the already massive PCIe bandwidth envelope, you can expect cutting-edge gear to lean heavily into these blazing fast PCIe interfaces.
Here are my expert tips for smoothly transitioning from PCI:
- Check motherboard expansion slots – when purchasing a new system, ensure it provides the latest PCIe 4.0 or 5.0 slots to maximize upgrade lifespan
- Evaluate next-gen bandwidth requirements – new GPUs and SSDs will require PCIe 4.0+ to prevent interface bottlenecks
- Check card compatibility – confirm any existing PCI gear you’re carrying over functions in a new PCIe mobo prior to purchase
- Plan a phase-out – shop for PCIe replacement cards for aging Sound Cards and WiFi Adapters
Welcome to the world of PCI Express! Feel free to reach out with any questions arise when making the move to this improved contemporary standard.
