PCI vs PCIe: Differences and Comprehensive Comparisons (Latest Updates)

PCI vs PCIe, what’s the differences? This post will share the details that you concern about most, including its slot, speed, compatibility, and so on. If you want to use one, here’s also a guidance for data migration.


By Irene / Updated on May 6, 2024

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PCI vs PCIe: What are the differences?

In a computer, data exchange happens through buses connecting devices like graphic cards, hard drives, SSDs, WiFi, and Ethernet to the processor subsystem. Peripheral Component Interconnect (PCI), Peripheral Component Interconnect eXtended (PCI-X), and Accelerated Graphics Port (AGP) were older bus protocols, now replaced by the current standard, PCI Express (PCIe). Why the PCIe can replace the PCI? What’s the differences?

PCI vs PCI Express in data transfer speed

One of the primary reasons for the transition from PCI to PCIe is the substantial increase in data transfer speed. While PCI has a data rate of 133MB/s, PCIe offers significantly higher speeds, with a data rate of up to 16GB/s for a 16-lane slot. PCIe speed varies based on lanes and versions, as illustrated in the Wikipedia PCIe performance diagram. This enhanced speed is important for modern computing needs, especially with resource-intensive applications and high-performance components.


PCI vs. PCIe comparison in interface

PCI uses a parallel interface, where individual buses are dedicated to each connected device. In contrast, PCIe employs a serial interface, sharing a common set of lanes for data transmission. The serial nature of PCIe contributes to its higher efficiency and faster data transfer rates compared to the parallel structure of PCI.


In summary, the shift from PCI to PCIe in professional computing is motivated by the demand for faster data transfer, the efficiency of a serial interface, streamlined motherboard design, and the direct connectivity to the CPU.

Currently, PCI, PCI-X, and PCIe cards coexist in the market. If you concern about PCI vs PCIe compatibility

However, as PCIe network cards provide compatibility with modern operating systems and faster speeds, computer hardware designers and manufacturers are increasingly incorporating PCIe into their latest products. The gradual replacement of PCI/PCI-X by PCIe is inevitable, and PCI-based cards are expected to become obsolete soon.

For M.2 PCIe SSDs:
If the graphics card uses PCIe 3.0 X8 lanes, and other PCIe 3.0 X4 ports connect NVMe SSDs, each SSD enjoys 4 GB/s throughput exclusively.
If the graphics card uses PCIe 3.0 X16 lanes, and the M.2 PCIe SSD shares 24 PCIe lanes with other devices, SSD speed is limited by DMI 3.0. Thunderbolt 3, M.2, and U.2 interfaces can't exceed PCIeX4 bandwidth. Despite sharing throughput, PCIe SSDs are faster than SATA SSDs, and DMI 3.0 throughput suffices as additional Southbridge devices usually don't operate simultaneously.

Migrate your Windows to a PCIe SSD

Once you understand the difference between PCIe and PCI, you might prefer using PCIe products. If your computer has a PCI-E interface using a Windows computer, you can definitely experience the high-speed benefits of PCIe.

To get this done, it's best to use AOMEI Partition Assistant Professional, a complete computer management tool. It lets you move just the operating system or transfer all your data, like files and programs, based on what you need. Now, let's go through the steps in detail.

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▌Migrate OS only:

Step 1. Start the installed AOMEI Partition Assistant Professional. Choose Clone > Migrate OS from the top section, and take a look at the introduction in the next window.

Migrate OS to SSD

Step 2. Choose the SSD as the destination disk. If there are partitions on this disk, mark the option "I want to delete all partitions on this disk 2 to migrate system to the disk."

Select Samsung SSD

Step 3. Resize the system partition on the target disk if you need to.

Resize Partition

Step 4. Please remember this note as it may be useful later on.


Step 5.  Return to the main interface, and then click on Apply to carry out the pending operations.


▌Transfer all the data:

Step 1. Run the installed AOMEI Partition Assistant Professional. Click “Clone" from the top menu, and select the "Clone Disk" feature.

clone disk

Step 2. Then choose the clone method to copy the selected disk and hit the “Next” button. If you are cloning a large hard disk to a smaller one, choose the first option, please.

Copy Disk Quickly

Step 3. Select a destination disk to contain all data from the source disk, and click “Next”. If the destination disk is an SSD drive, you can tick “Optimize the performance of SSD” option during the process, which can help make 4K alignment on SSD partitions.

Select Destination Disk

Step 4. You can adjust partition size in this window if you choose “Clone Disk Quickly” above. After everything is done, hit on “Next” to continue.

Edit Disk

1. Clone without resizing partitions: All partition will be cloned to the target disk as the original partition size. It is available when the target disk is large enough to hold all partitions on the source disk.
2. Fit partitions to entire disk: All partitions will be cloned to the target disk and take up its full capacity according to the original partition size proportion.
3. Edit partitions on this disk: You can change every partition size on the target disk as you need.

Step 5. A note will appear to tell you how to boot from the cloned disk. You can read it carefully, and then click “Finish”.


Step 6. Click “Apply” to commit the pending operation.



If you are curious about PCI vs PCIe, this passage highlights distinctions in their slot, speed, compatibility, and more. If you wish to enjoy the benefits of a PCIe SSD, you can use AOMEI Partition Assistant to transfer the data based on your needs.

Afterward, it is advisable to use the software for further management. For example, you can easily merge/resize/delete/move partitions, extend drive space, rebuild corrupted MBR, convert between GPT/MBR, and so on. For Windows Server users, please choose the AOMEI Partition Assistant Server edition.

Irene · Staff Editor
Irene is an Editor of AOMEI Technology. She devotes herself in giving insightful thoughts on common computer problems with simple and clear guidance. Irene loves to help people solve problems and explore more solutions on relevant issues. She loves reading, singing and travelling.