What does PCI Slot mean?
A PCI slot is a built-in slot on a device that allows for the attachment of various hardware components such as network cards, modems, sound cards, disk controllers and other peripherals.
It was often a component of traditional do-it-yourself (DIY) desktop computer design.
Techopedia explains PCI Slot
These days, the PCI slot has largely become obsolete. First, new standards have emerged for making the actual device connections, and secondly, new protocols have replaced some of the traditional ones for connecting to the modernized bus.
Over time, the PCI-Express or PCI-e new bus model replaced the traditional PCI. In that sense, it's obsolete to talk about a PCI slot. Newer devices would instead have a PCI-e slot.
Desktop to Laptop
Another major hardware and device change has been the shift in markets from traditional desktop computers to laptop computers. In the days of the traditional PCI slot, desktops were the only option, and then later, the dominant purchase choice.
Now, laptops have become much more of a common model for computing, and few of them have any type of traditional PCI slot, at least one that is easily accessible to the user.
Utilizing a PCI (PCI-e) slot on a laptop is often much harder than it would have been with a traditional desktop design that had a dedicated PCI slot built into its frame. With laptops, users face various challenges in utilizing an available PCI or PCI-e slot.
First, there's diagnosis, where the user has to run software to see if a PCI or PCI-e slot is available. Then they will often have to open the frame of the laptop in order to install a device on a PCI or PCI-e slot.
After all that is done, and a device has been successfully connected, users will be likely to face various problems with adequate power and cooling. Unlike traditional desktop designs, laptops are not made with a lot of space to spare, and that means more challenges in integrating new hardware inside the frame. Particularly with newer designs, this task has gone from impractical to impossible.
While there are some small cooling devices that can be added to support the processing power needed for additional PCI and PCI-e connected devices, these are not the norm in the world of computer manufacturing today.
The NVM Standard
That shift from traditional hardware utilizing PCI bus design to new hardware is also evident in new protocols that are replacing the PCI-e protocol for connecting devices to a PCI-e bus.
A protocol called non-volatile memory express or NVMe is taking over from the PCI-e protocol model. It is made specifically to work with solid-state drives: for example, many of these devices will utilize NAND flash memory design.
Experts point out that NVMe is supposed to take advantage of the low latency and internal parallelism of solid-state drive models.
All of these changes have made a conventional PCI slot pretty much obsolete.
DIY builders can still utilize this kind of technology on legacy or retro equipment, but moving forward, new types of connectivity and device handling will replace some of those traditional models, and it's much more likely for additional sound and processing power to be built into a device design than for users to add it themselves in some aftermarket way.