PC ComponentsGPU

Which PCIe Slot for GPU?

Pcie Slot

Peripheral Component Interconnect Express (PCIe) is a hardware interface introduced in the early 2000s to enable high-speed serial communication between the CPU and peripheral components. These include graphics cards, solid-state drives, ethernet cards, and high-speed Wi-Fi cards.

If your computer has several PCIe slots, it may not be clear which one you should use for GPU. Most PC build technicians believe that you should always put your GPU in the first slot for better performance, but is this true?

Quick Answer

It’s no secret that the first PCIe x16 slot of your motherboard is the most preferred PCIe slot when it comes to GPU connection. This is because it usually has 16 PCIe lanes and offers the highest throughput than the other PCIe slots on your PC. It may be the only fully-decked PCIe x16 slot on the motherboard.

This article will discuss the basics of PCI express, the difference between PCIe slots and PCIe lanes, and which PCIe slot to use for GPU setups.

Overview of Which PCIe Slot Is Best for Your GPU

Most PCs come with PCIe slots (i.e., X1, X4, X8, X16, and X32). In most cases, the number indicated after X represents the number of lanes the PCIe slot has, and the lanes are just paths for data to travel on. For instance, an X1 PCIe slot may mean it only has one lane, while X16 may have 16 lanes. The more the lanes, the faster the speed of data exchange.

Even though PCIe lanes are often used interchangeably and named the same as PCIe slots, they don’t always correspond. The main difference is that PCIe lanes are physical wires running from PCIe slots to the motherboard, while PCIe slots are mechanical slots designed to allow high-speed connection to the CPU through PCIe lanes. 

Don’t always assume that an X16 PCIe slow will have X16 PCIe lanes. In some cases, you may install your GPU into an X16 PCIe slot, but it runs at just X8 or X4 PCIe lanes

Also, when it comes to PCIe slots, the data transfer rate in each lane doubles with every new generation. For instance, the PCIe version 1.0 X16 has a transfer rate of 4.00 GB/s while the PCIe version 2.0 has a speed of 8.00 GB/s.

Why Does PCIe Slot Choice Matter?

If your motherboard has several slots, the PCIe slot choice matters because the graphics card may function differently with each slot. Some motherboards treat the first slot as the primary slot, while others treat all the slots as the same.

It’s a no-brainer to put your GPU in the first slot for motherboards with a primary slot because it’ll perform better than all the other secondary slots.

However, if your motherboard treats all PCIe slots the same, you can use any of the other slots for GPU. If installing the GPU in the first PCIe slot obstructs other components, installing it on the other slots is advisable. You can also review the motherboard’s manual to see if there’s a recommended slot. 

GPUs transfer a lot of data over the PCIe-Bus. For this reason, ensure that the PCIe slot you select has access to 8-16 PCIe lanes. If you run your graphics card without the required PCIe lanes, you may experience throttling or reduced performance.


This article explains that the PCIe slot choice matters when installing a video card. The first PCIe slot is preferred because it allows your graphics card to run at its optimum level. If you decide to use the secondary PCIe slots, you may experience minimal performance loss, but the graphics card will work fine.

Frequently Asked Questions

Are all PCI Express slots the same?

No, PCIe slots come in different form factors or sizes. Install your GPU in the first PCIe slot, which usually runs at X16 PCIe lanes, if you want the best performance.

Why do computers have PCIe slots?

PCIe slots have two main advantages. First, they enable high-speed serial communication between the CPU and peripheral components. They also allow the PC user to add new devices to their computer without replacing the motherboard.

For instance, you can upgrade your video card by removing the old one and installing a new one to get better performance on the same CPU.

What types of PCIe slots are on my motherboard?

Every computer motherboard is unique, so to determine the PCIe slot your computer has, look for information in the motherboard’s manual. Alternatively, you can visually examine the motherboard to determine the type of PCIe slots.

Do you I to install the GPU in the first PCIe slot?

The GPU should always go into the first PCIe x16 slot if you want the best performance. Some motherboards treat the first PCIe slot as the primary slot, and thus it has a better performance capability than the other slots.

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