If you plan to build an ultimate gaming rig, or if you have an extra graphics card lying then you if you can fit both of your graphics card on your motherboard or not.
Well the answer to that question depends upon what motherboard you have and also, to an extent, what graphics card you have.
In order to figure out whether your motherboard supports dual graphics cards or not you need to have the right motherboard chipset as well as two PCIe x16 slots.
In addition to that, there are many other factors that come into play when fitting two graphics cards on a motherboard such as its form factor as well as its the amount of PCIe lanes the slot has.
In this guide I will comprehensively answer the question “can I fit two graphics cards in my motherboard” by talking about various important aspects surrounding it.
How to Check If Your Motherboard Supports Two Graphics Card?
To figure out whether your motherboard supports two graphics cards or not you need to figure out
- What chipset the motherboard has
- Whether it has two full x16 slots or not
1. Motherboard Chipset for Dual Graphics Cards
The motherboard chipset model plays a very important role in determining whether it supports dual graphics cards or not.
Both Intel and AMD have several motherboards.
- H and B series in the budget and midrange segments.
- Z series in the premium market segment
Similarly AMD has
- A and B series in the budget and midrange segments
- X series in the premium market segment.
As far as support for dual graphics card goes, that depends upon whether you have two AMD graphics cards or two NVIDIA graphics.
Motherboard Chipset for Two NVIDIA Graphics Cards:
If you have two NVIDIA Graphics cards, then the motherboard needs to support SLI.
SLI is supported by the following chipsets.
- AMD B series such as the AMD B550
- AMD X series such as the AMD X570
- Intel Z series such as the Z590
Motherboard Chipset for Two AMD Graphics Cards:
If you have two AMD Graphics cards, then a motherboard needs to have crossfire support.
AMD Crossfire is supported by a much wider range of motherboard chipsets compared to NVIDIA SLI. These include:
- Intel H series such as the H570
- Intel B series such as the B560
- Intel Z series such as the Z590
- AMD B series such as the B550
- AMD X series such as the X570
It is worth noting that certain chipsets such as the AMD A series chipset i.e AMD A520 and Intel H*10 chipsets such as the H410, H510 OUTRIGHT lack support for dual graphics cards.
However, knowing what chipset your motherboard has and whether the chipset supports dual graphics cards or not is only half of the story. You also need to have the right amount and type of slots.
Which brings us to the next point.
The Motherboard Must Have Two PCIe x16 Slots with Enough Lanes
Another important characteristic in determining whether you motherboard supports dual graphics card or not is the PCIe slot.
You need to have two PCIe x16 slots on the motherboard.
However, just because a motherboard has two PCIe x16 slots does not mean that it will handle two graphics cards!
Not all PCIe x16 slots are created equally. You need two x16 slots capable of running in the x8/x8 mode or x16/x4 mode.
For NVIDIA SLI you need two PCIe x16 slots capable of working in x8/x8 mode. For AMD Crossfire you need two PCIe x16 slots capable of working in x16/x4 or x8/x8 configuration at least.
Before I talk about the x16 slot and the x8/x8, x16/x4 modes, let me explain what PCIe lanes are.
What are PCIe Lanes?
The number after the letter ‘x’ in x1, x4, x8 and x16 generally denotes the number of PCIe lanes a slot has.
PCIe lanes are like information highways that carry data back and forth from the CPU and the expansion card installed on the slots.
The more PCIe lanes a slot has, the information it can carry. More demanding devices like graphics card require more PCIe lanes compared to low demanding cards like a WiFi network card.
Read in Detail: What are PCIe Lanes?
The number of PCIe lanes a computer has are limited and are determined by the motherboard chipset as well as the CPU you have.
The following table shows how many PCIe lanes certain chipsets offer.
- 12 x v4.0
- 16 x v3.0
- 12 x v4.0
- 12 x v3.0
(Minus overclocking Support)
- 6 x v4.0
- 8 x v3.0
- 12 x v3.0
|B460||16||Mid Range /
|B560||12||Mid Range /
The higher the number of PCIe lanes your system has, the more PCIe slots it can have and the more demanding devices, like graphics cards, it can interface with.
How Many PCIe Lanes do Graphics Cards Need?
Now graphics cards being the most demanding expansion cards that you can install on a PC ideally require 16 lanes or an x16 slot. In fact the connector on the graphics card is of x16 size. It cannot fit in any other slot.
However, graphics card can also work at a lower lane count:
- NVIDIA graphics cards can work on an x8 slot (with 8 lanes)
- AMD graphics cards can work on an x4 slot (with 4 lanes)
Installing a graphics card, that otherwise requires 16 lanes to work at its full potential, looses a bit of performance when installed on an x8 or and x4 slot.
Also Read in Detail: Which Slot for GPU is Ideal and Why?
The Peculiar Case of the x16 Slot: Not All Offer 16 Lanes!
x16 slots are a bit a devious. Now not all x16 slots offer the full 16 lanes.
Take for instance the following Gigabyte GA P67A UD3 motherboard, you can see that the second x16 slot (bottom blue slot) has the full x16 length but only offers 4 PCIe lanes. This slot is called x16(x4) slot.
Now with this motherboard I can do an AMD Crossfire or have two AMD graphics cards installed – because AMD GPUs can work on an x4 slot – but I cannot install two NVIDIA graphics cards.
Hence I can use the x16/x4 configuration. Meaning the first AMD graphics in top slot will work at 16 lanes and the second AMD graphics card on the bottom x16(x4) slot will work in x4 mode – it will loose performance in this slot.
NVIDIA SLI: Does My Motherboard Support SLI
Now in order for your motherboard to support two NVIDIA graphics cards in SLI mode you need to have two PCIe x16 slots capable of running in the x8/x8 mode.
Take for instance the following SLI capable motherboard:
This motherboard has 3 x PCIe x16 slots.
- The first PCIe x16 slot works in x16 or x8 mode
- The second PCIe x16 slot work in x8 or x0 mode,
- The one on the bottom only work in x4 mode.
So if you have two NVIDIA cards, you will occupy them in the first and second slot.
What this means is that when you install a graphics card or the second PCIe x16 slot, it will force the first x16 slot to divide its lane between itself and the second slot.
It is worth noting that while this motherboard does support two NVIDIA graphics cards. For with AMD graphics cards, it can support 3 of them – again AMD GPUs require only 4 lanes to work.
Also Read: Do All Motherboards Fit in Any Case?
Motherboard Form Factor Also Determines Whether It Can Support 2 Graphics Cards
The motherboard form factor (size) also to an extent determines whether your motherboard can fit two graphics card.
There are three common form factors:
- ATX or Standard ATX: 12 x 9.6 inches
- Micro ATX: 9.6 x 9.6 inches
- Mini ITX: 6.7 x 6.7 inches
Mini ITX motherboards, as you see above, do NOT support two graphics cards as they only have one x16 slot.
The larger ATX and micro ATX motherboards have enough space to offer 2 x PCIe x16 slot.
Also Read: Can You Use AMD GPU with Intel CPU?
Also Read: Can B Series Motherboards Overclock?
How Many Graphics Cards can a Motherboard Support?
A commercial motherboard can support upto 3 graphics cards (upto 2 NVIDIA graphics cards or upto 3 AMD graphics cards).
A workstation grade motherboard such as those featuring the x299 or the TRX40 chipsets can handle four or more NVIDIA or AMD graphics cards.
Also Read: How to Check Form Factor of Motherboard?
Can I Run 2 Different Graphics Cards on My PC?
Generally no, you cannot have 2 different graphics on the same system. They have to be the same. However, AMD does give some leeway in selecting two graphic cards.
Here is the detail article: Can You SLI Two Different Graphics Cards?