Which PCIe Slot for Wireless Card?

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A wireless card requires only a PCIe x1 slot – which also happens to be the smallest in terms of physical size and throughput rate.

This is because even the newest WiFi 6 PCIe cards have a throughput (speed) of about 2.4 Gbps (300 MB/s) on 5 GHz frequency. Contrast this to the data rate of a single PCIe x1 slot that can handle throughput rate of 985 MB/s and 1969 MB/s on version 3.0 and 2.0 respectively!

In this article we talk in detail about which PCIe slot for wireless card is most suitable. In doing so we will look into why that is so, talk about PCIe slots, version, bandwidth and all the related jargon.

If you are looking for a simple answer though, then PCIe x1 slot is the one to go for. Currently, there is no PCIe wireless card powerful enough to leverage the bandwidth of a higher PCIe lane count and hence none require a larger PCIe slot.

Let us look into PCIe Wireless Card, PCIe Lanes and PCIe Slots a bit.

PCIe Lanes, Bandwidth, Version and Slots

In order to understand why a PCIe x1 slot is sufficient for WiFi card, you have to understand a bit of PC jargon.

A PCIe lane is basically like a highway through which data travels to and fro the PCIe slot. The more lanes a PCIe slot has, the higher would be the throughout (speed in layman’s terms) of the slot the expansion card attaches to attaches.

The more demanding an expansion card is, the more PCIe lanes it required.

The throughput rate of each lane differs from generation to generation.

Versionx1
(GB/s)
x2
(GB/s)
x4
(GB/s)
x8
(GB/s)
x16
(GB/s)
1.00.2500.500 1.0002.0004.000
2.00.5001.0002.0004.0008.000
3.00.9851.9693.9387,87715.754
4.01.9693.9387,87715.75431.508
5.03.9387,87715.75431.50863.015
6.07.87715.75431.50863.015126.031

Table: PCIe version and lane throughput.

The table above shows that the throughput of a single PCIe lane, x1, is 0.50 GB/s on PCIe v.2. However a single PCIe x1 v3.0 lane has a 0.985 GB/s throughput.

Different PCIe slot sizes have different amount of PCIe lanes.

Common sizes include, x1, x4, x8, x16.

pcie slots labelled and watermarked

 

It is important to understand that the amount of PCIe lanes your system has are limited. Hence it is wise to understand the lane requirement of new cards and the overall you have available.

For instance, if you have 20 PCIe lanes in your system, and have a graphics card taking up 16 lanes, an M.2 expansion card taking taking 4 lanes, you would not be able to install an additional WiFi card to a free x1 slot.

Also Read:

So Which PCIe Slot for Wireless Card?

Which PCIe Slot for Wireless Card

Image: ASUS AX3000

As mentioned earlier, the x1 slot is more than enough for the contemporary WiFi 5 and WiFi 6 protocols.

Why is x1 Sufficient for a Wireless Card?

This has all to do with bandwidth requirement of the card. The bandwidth requirement of a WiFi 6 card does not even saturate a single PCIe 2.0 lane, let alone that of version 3.0 and 4.0.

The transfer speed of PCIe slot differs from version to version. Currently, the most common PCIe version is the Version 3.0. However, on older or entry level motherboards you may find some slots operating at Version 2.0 as well.

As seen in the table above PCIe Version 3.0 has a transfer speed of about 1 GB/sec per lane. This is sufficient to support the transfer speed requirement for the wireless add in cards. Why? let us look at an instance:

An average PCIe WiFi 6 card promises speed of 2.4 Gbps on 5 GHz frequency. 2.4 Gigabits per second equals 300 MegaBYTE per second. Note the difference between bits and bytes. They are NOT the same thing.

As we saw earlier above, a PCIe x1 v2.0 slot has a speed of 500 MB/s, likewise PCIe x1 v3.0 caps at 985 MB/s and PCIe x1 v4.0 at 1969 MB/s.

So while the very old and ancient PCIe x1 v1.0 with their 250 MB/s throughput rate cap may not be sufficient to handle the newer gen WiFi 6 speed to its max capability the rest of the generations of PCIe slots are more than sufficient to handle WiFi 6 cards.

Also Read: Onboard Wi-Fi vs Wi-Fi Card vs Wi-Fi USB

Cross Compatibility

It should be noted, however, that while ideally an x1 slot should be used, you CAN fit the Wireless card in other larger slots i.e the X4, X8 or even the X16.

But, you should also note that installing the WiFi card in a larger PCIe slot will not give any kind of performance boost to it.

Plus, doing so would mean that you will have to sacrifice a precious larger PCIe slot that can otherwise be used for larger expansion cards like RAID controllers or SSD Add In Cards.

For instance, a PCIe x16 is the largest slot available on a consumer grade motherboard. If you occupy that with a WiFi card that requires a mere x1 slot, you will have wasted a card that can be used for a graphics card instead.

Also Read: Can I Use a PCIe 3.0 Card in a 2.0 Slot?

Do You Need to Provide External Power to the Wireless Card?

No, you do not. Unlike the graphics cards that are installed on PCIe X16 slot and require direct power from the PSU, the WiFi card does not.

WiFi card consumes very little power and therefore, they can be powered through the PCIe slot itself.

A PCIe slot itself can provide 75 Watts of power.

Making Sure You have Enough PCIe Lanes

This is a very important consideration when installing newer PCIe devices to your computer

Every PC has only a limited amount of PCIe lanes. Using the PCIe X1 slot means that you are using one PCIe lane of your computer.

The total amount of PCIe lanes are determined by the processor you have as well as your motherboard chipset.

You can find out about the amount of lanes you have by looking at the processor and the motherboard chipset specsheet.

In order to install a WiFi Card and make it work, you need to make sure you have one PCIe lane available to you.

An Example

nvidia rtx 2080

Image: NVIDIA RTX 2080. Graphics Cards can take 16 Lanes.

As mentioned earlier, the amount of PCIe lanes you have are limited so you have to be careful when building your system and procuring newer expansion cards like a WiFi card.

Typically an average processor offers 16 PCIe lanes and the motherboard may offer 4 or more PCIe lanes. So lets say you have 20 PCIe lanes available to you.

Say you install a graphics card on an X16 slot and a RAID controller on an X4 slot. They both will occupy 16 and 4 lanes respectively, totaling 20.

Hence, installing a WiFi card, even if you have a free X1 slot available, will not allow it work since all total lanes you have are already in use.

On the other hand, if you only have a single graphics card installed and nothing else, then you can go ahead with using the X1 slot for your WiFi card. With this configuration you will have occupied 17 out of 20 lanes (16 for graphics card and 1 for WiFi card).

Therefore, you will still have 3 PCIe lanes available which can be used for other devices.

In short, you will need to manage your total PCIe lanes and the amount of expansion cards you install.

Final Words

Here we looked at a common question asked by those who are new to PCIe configuration and expansion cards i.e which PCIe slot for wireless card is suitable?

The simplest answer is the X1 slot and we looked at the reason why above. However, if you do NOT have an X1 slot available, you can go ahead and install the WiFi card in X4, X8 or even on an X16 slot but you will not see any performance boost.

Again before installing any PCIe expansion card like the WiFi card, it is essential that you make sure your PC has enough PCIe lanes to support your card.

This is especially true if you already have a plethora of devices connected to your motherboard. In case if you have no device attached, or if you only have a single graphics card connected, then there is a high certainty that you will have enough PCIe lanes left to support the WiFi expansion card as well.

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Author:

Atif Qazi
Atif Qazi is the founder of PCGuide101. He is a digital nomad who loves everything PC. He is a PC builder, tech enthusiast, engineer, and a lover of single player lore-rich RPG games.

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