PCIe slots can be occupied with numerous kinds of expansion cards/add-in cards. Graphics cards are one of the most common devices that you plug into a PCIe slots. You can also add network cards, SSD expansion cards, sound cards, storage controller cards, RAID controllers, video capture cards, TV tuner cards and Risers cards to the PCIe slots.
As you can see, the PCIe slot is very versatile. It can accommodate a wide range of components so that you may design your system to your liking.
If you are a gamer, then you may want to install a Graphics card. If you are building a NAS setup, you may want to add storage controllers and more SATA ports. If you are missing network capability on your PC, you can add a network adapter and if you are an audiophile, you can add a high end dedicated sound card to the PCIe slot.
The possibilities of what you can add are vast and in this article we will go through various devices to understand what things can be plugged in PCIe slots and what their functions are.
How is Expansion Done on Motherboards?
There are basically two protocols that you commonly use in order to add components to your motherboard.
SATA is a protocol that is generally used to connect hard disk drives, SATA SSDs and optical drives.
PCIe, on the other hand, is a protocol that is used to connect High Speed Input Out devices (HSIO). These are devices that have a high bandwidth requirement.
SATA protocol at the moment with its version 3.0 caps at about 750 MB/s (6Gbps) bandwidth.
PCIe, on the other hand is multiple folds faster than this. The PCIe x16 slot conforming to PCIe v4.0 has a bandwidth of about 31.5 GB/s. In fact a single lane PCIe x1 v4.0 slot has a bandwidth almost three times as much as a SATA 3 slot i.e 1.969 GB/s or 1969 MB/s on a single PCIe v4.0 lane vs 600MB/s on SATA 3.
The point being made here is that PCIe slots are used to plug in demanding and specialized components.
Also Read: How Much is a Motherboard?
There are Different Sizes of PCIe Slots
PCIe expansion cards have different lane and slot requirements. As such, there are different sizes of PCIe slots.
The most common slots are as follows:
- x16 – This slot has 16 PCIe lanes – Used for cards that require a high bandwidth like graphics cards; these are the largest slots on the motherboard.
- x8 – This slot has the same size as an x16 slot but half the PCIe lanes. This is also commonly used for graphics cards or for M.2 NVMe SSD expansion cards.
- x4 – This slot has four PCIe lanes – This also has the same size as an x16 slot. It is often used for single M.2 NVMe SSD expansion card; it is also used for SATA 3 expansion cards and raid controller, high speed 10G network adapters, 4k video capture cards.
- x1 – Smallest expansion slot – good for almost any other cards like asound card, average 1G network adapters (i.e wireless cards), FHD video capture cards, USB expansion cards etc
It is recommended to brush up your knowledge on PCIe lanes, version and slots in order to have a better understanding of the topic at hand.
Let’s Look at What Things Can Be Plugged in PCIe Slots
The following are some of the most common devices that you can add to the PCIe slots:
- Graphics Cards
- Sound Cards
- Ethernet Network Cards
- Wireless + Bluetooth Network Cards
- Video Capture Cards
- SATA Expansion and RAID Controller Cards
- M.2 NVMe Expansion Cards
- TV Tuner Cards
- Port Expansion Cards
- Riser / Splitters
1. Graphics Cards (GPUs)
One of the most common peripherals installed on a PCIe slot is a DEDICATED graphics card – the processing module that allows all the visuals you see on the screen to be painted. This is a device particularly of interest to gamers and cryptominers.
Many CPUs come with an INTEGRATED graphics card. These are fairly simple and can suffice for average users.
For advanced users like gamers, designers and simulators, beefier DEDICATED graphics cards are needed.
In fact, a graphics cards is one of the most major investments for any enthusiast PC builder.
In the case of a desktop, the only way to add a dedicated graphics card is via PCIe x16 slot. Majority of the graphics card are designed to utilize 16 PCIe lanes and thus they require the full PCIe x16 slot to function at their best capacity.
Note on Integrated (iGPU) vs Dedicated Graphics Card
As mentioned iGPUs are built into the CPUs. These are good enough for an average users. Dedicated graphics cards are standalone devices designed by NVIDIA or AMD that plug into the PCIe slots on your motherboard.
2. Sound Cards
Image: Creative Blaster AE-9 internal sound card. One of the most advanced and expensive internal sound card.
Computers can process sound natively as all motherboards have a built in sound processing chip.
But in the case of creators, gamers, enthusiasts, or professionals who need a higher grade of sound output, investing in a sound card is the next logical step.
These can add better audio ports and quality to your system and even increase audio channel support. Another advantage is the reduction of interference which can distort sound quality or lead to noise.
While a dedicated sound card, as above, is not a match for professional audio systems and interfaces, they can be great for audiophiles and intermediate audio producers.
Sound cards require a PCIe x1 slots.
3. Ethernet Network Cards
While most motherboards come with Ethernet support. On some of the older motherboards, this could be missing. Hence this could warrant an investment on Ethernet network adapters.
Plus, on basic mainstream boards you can only get an average gigabit network speeds. With dedicated PCIe network cards, you can choose to have even a 10G or faster speeds.
The ASUS XG-C100C above is high speed 10G, or 10 Gbps, network card that requires an X4 slot (v3.0). Weaker Gigabit, or 1 Gbps, network cards only require an x1 slot (v3.0).
4. WiFi + Bluetooth Network Cards
In addition to Ethernet network cards, you also get network cards that can add WiFi + Bluetooth functionality to your PC.
A WiFi Network card, even conforming to the newer WiFi 6 protocol, requires only an X1 slot.
Also Read: Do Motherboards Come with WiFi?
5. Video Capture Cards – AKA Game Capture Card
Image: Elgato 4k 60Hz video capture card requires an x4 PCIe slot.
Video Capture cards are used for recording the content on the screen. They can also be used to stream the same content to viewers over the internet.
These can come in handy for online game streamers and entertainers, and are particularly good for those who build a dedicated streaming PC or have a gaming console.
Other than gamers and streamers, these are also used by content creators and vloggers.
Essentially, a video capture card helps in encoding the raw footage into data that a computer can understand. This can then be edited or streamed.
An FHD PCIe video capture cards require an x1 slot. However, 4K video capture cards require more PCIe bandwidth and thus require an x4 slot.
6. SATA Expansion and RAID Controller Cards
Image: While most SATA expansion cards are simple, the 10Gtek SAS 9211-8I is an advanced RAID controller with 8 SATA port capacity. Note that this has SAS connectors. You will need a SAS to 4-SATA ports cable in order to have a maximum of 8 SATA ports available to you.
PCIe slots can also be used to increase the storage capacity of your system. If you have a limited amount of SATA 3 ports on your motherboard for connecting SATA hard drives, you can get a PCIe SATA expansion card.
The size of the SATA expansion card and the type of slot it requires depends on factors like how many SATA slots it has and whether it has a RAID controller or not.
You can find SATA 3 expansion card for x1, x4 and x8 slots.
7. M.2 NVMe Expansion Cards
Image: NVMe expansion card. Offers a single M.2 NVMe slot and occupies x4 PCIe slot.
PCIe NVMe SSD are the fastest hard drives available. An average SATA 3 spinning hard disk drive can reach speeds of only 200 MB/s in very ideal conditions.
A PCIe NVMe SSD can reach speeds of upto 7000/5100 (Read/Write) MB/s such as the Samsung 980 Pro. This is many folds faster than an average hard drive.
Many newer motherboards do come with at least one NVMe M.2 slot. However, if your motherboard lacks the M.2 slot or if you want to add another NVMe SSD to your system, then you can invest in an NVMe SSD expansion cards.
Note that each M.2 NVMe slot requires 4 PCIe lanes. As such, the smallest you can find requires an x4 PCIe slot.
8. TV Tuner Cards
Image: Hauppauge 1196 TV Tuner Card
Up next in the list of what things can be plugged in PCIe slots is a TV Tuner card. Simply put, TV Tuner cards let your PC work like a TV. They allow it to directly receive TV signals, decode it and show you TV channels.
These cards are relatively inexpensive and can come in handy in a variety of situations. Some can be plugged in via USB, but there are many which get connected directly to the motherboard via PCIe ports.
These require a PCIe x1 slot.
9. Port Expansion Cards – Thunderbolt, USB
Image: Gigabyte GC-Titan Ridge 2.0 Thunderbolt 3.0 expansion card.
If you want to have more IO on your PC, a PCIe port expansion card is the way to go.
Whether you want to add more USB Type A ports, the newer Type C port or even a Thunderbolt 3.0 port to your PC. You can do so with port expansion cards.
It should be noted, that you NEED TO HAVE THE RIGHT HEADER TO ADD THE CORRESPONDING PORT EXPANSION CARD. For instance, to add a Thunderbolt 3.0 expansion card like the one shown above, your motherboard needs to have a Thunderbolt 3.0 header.
Depending upon the amount and type of port, these cards require x1 or x4 PCIe slot.
10. Riser Cards
Riser cards are essentially PCIe port splitters. Just like port expansion cards, PCIe riser cards add extra ports to your PC. Only that the ports they add are PCIe.
Caution: MORE PCIE SLOTS DOES NOT EQUAL MORE PCIE LANES OR HIGHER BANDWIDTH. To learn how to add more PCIe slots, follow this article:
Riser cards are very popular among cryptominers and for creating crypto mining rigs with multiple graphics cards.
Summary of Expansion Cards and Their PCIe Lane Requirements
|Card||PCIe Lane |
|NVIDIA Graphics Card||16 or 8||16 ideally
8 in case of SLI
|AMD Graphics Card||16, 8, or 4||16 ideally
8 or 4 in case of crossfire
|Ethernet Network Card||1 or 4||1 in case of 1 Gbps (v3.0)
4 in case of 10 Gbps (v3.0)
|WiFi Network Card||1|
|Video Capture Card||1 or 4||1 in case of 1080 capture (v3.0)
4 in case of 4k capture (v3.0)
|SATA Expansion and|
|1, 4, 8||The lane requirement depends upon number of SATA slots, and whether it has RAID Controller|
|M.2 NVMe Expansion Card||4|
|TV Tuner Cards||1|
|Port Expansion Card||1 or 4||Depending upon the type and number of port. Thunderbolt 3.0 port, for instance, requires 4 PCIe Lanes (v3.0)|
|Riser/Splitter||1, 4, 8, 16|
Cross and Backward Compatibility
The PCIe standard is cross compatible meaning an x4 card can be installed in an x16 slot – but you should refrain from doing this unless absolutely necessary otherwise you will be wasting your precious x16 slot on a smaller card.
The PCIe standard is backward compatible, so an older PCIe card operating on PCIe 2.0 standard will fit in a PCIe 3.0 slot. However, the interface only operates at the maximum speed of the slower of the two.
Here I talked in detail about some of the most common devices that can be plugged into a PCIe slot. It is very important that you learn what PCIe slot and lanes are.
You see, each PCIe device requires a certain amount of PCIe lanes but the amount of PCIe lanes you have in your system are limited. In my blog here I have talked in detail about PCIe lanes. So make sure you are well versed with the concept if you plan to build your PC or install a new device.