The short and simple answer to your question whether you can use a PCIe 4.0 SSD on your existing motherboard is a yes! You can certainly use the PCIe 4.0 SSD on any motherboard as long as it has an NVMe M.2 slot.
However a very important thing to note is that the performance, or the speed, that you get from your v4.0 SSD will depend upon the version of the PCIe interface the M.2 slot on your motherboard conforms to.
Basically, if you have a v3.0 PCIe slot and a v4.0 device, the overall transfer speed will conform to the slower of the two. This is basically called link-width negotiation and it is the idea that makes PCIe interface backwards and cross-compatible across generations.
In other words, if you have a motherboard with a V3.0 NVMe M.2 slot and you install a V4.0 PCIe SSD on it, the SSD will work, but it will get significantly bottlenecked! So you will essentially have wasted the potential of a faster drive by putting it into an older gen slot.
To operate a PCIe 4.0 SSD to its max potential, you need to have a motherboard with M.2 NVMe slot that also conforms to the PCIe v4.0.
Only the latest motherboards from Intel and AMD such as those featuring AMD 500 Series (X570, B550), Intel 500 Series (Z590, Intel B560 etc.) and Intel 600 Series chipsets supports V4.0 NVMe M.2 slots for 4.0 PCIe SSDs.
In this text we will explore in detail whether you can use a PCIe 4.0 SSD on your existing motherboard or not. For this, you will need to equip yourself with some basic knowledge regarding the PCIe protocol.
PCIe Lanes and Their Version
PCIe lanes are essentially pipelines that send information to and from the PCIe slot (M.2 Slot in this case) and the CPU.
The number of PCIe lanes a PC has are limited. The CPU and the motherboard model and make determine the amount of PCIe lanes you have in total.
Each PCIe lane has a certain throughput rate (speed) depending upon the version it conforms to.
So a single V3.0 PCIe Lane has a throughput rate of 0.985 GB/s, whereas a single V4.0 PCIe lane has a throughput rate of 1.969 GB/s.
Every successive PCIe generation therefore DOUBLES the throughput rate as compared to the previous version.
The following table shows the PCIe version and their corresponding speed based on different amount of lane counts.
An NVMe M.2 Slot SSD uses 4 PCIe lanes.
PCIe Version and the Ramifications for an NVMe SSD
Since an NVMe SSD uses four PCIe lanes, the generation of both the SSD and the M.2 slot it plugs into has a direct impact on the speed of the drive.
- x4 v3.0 lanes have a throughput rate of 3.938 GB/s.
- x4 V4.0 lanes have a throughput rate of 7.877 GB/s.
Hence a PCIe 4.0 SSD can have twice the speeds as compared to a V3.0 SSD theoretically.
Practically speaking though, while the speeds of the older PCIe Gen 3 SSD reached a max speed of 3500MB/s, the PCIe Gen 4 SSDs can reach about 6500 MB/s.
Techspot has a great article on PCIe V4.0 vs 3.0 SSDs if you are interested in benchmarks.
PCIe Interface is Backwards Compatible
The beauty about PCIe interface is that you can put a newer device in a slot conforming to an older PCIe version and vice versa.
However, as mentioned earlier, the link speed between the device and the slot will work at the slowest of the two.
Meaning, if you attach a V4.0 device in a V3.0 slot, then the max transfer speed will not exceed that of the the slot’s – hence your V4.0 device CAN get bottlenecked IF it has the potential to generate a higher amount of data than the slot supports.
Which brings us to the next point:
V4.0 M.2 Slot for V4.0 PCIe SSD is Thus Essential
If you do not want your V4.0 PCIe SSD to get bottlenecked, then you require a V4.0 M.2 NVMe Slot on your motherboard!
Recall from earlier that an M.2 slot uses four PCIe lanes and that V3.0 M.2 slot can have a max theoretical throughput rate of 3.938 GB/s.
Therefore, if you were to install a version 4.0 SSD on a V3.0 M.2 slot, it will work, but the performance would get seriously reduced.
Hence, to get the best out of your V4.0 SSDs, you need to have a V4.0 M.2 slot as well.
As mentioned earlier, currently only a handful of latest motherboard chipsets offer M.2 slots conforming to V4.0.
How To Figure Out the Version of Your NVMe M.2 SSD Slot?
Basically, the PCIe version that your PC in general and the M.2 SSD slot in particular conforms to depends upon your motherboard chipset as well as upon the CPU you have.
Read in Detail: How to check PCI Express Slot Version?
Motherboard Chipset PCIe Lanes vs CPU PCIe Lanes
A typical PC has PCIe lanes coming from both the CPU as well as from the motherboard chipset.
In addition to that, the PCIe lanes coming from the CPU and the Motherboard chipset DO NOT have to be of the same generation.
Hence, it is possible to find on the same motherboard some slots conforming to V4.0 and others conforming to the older V3.0.
In fact, on AMD B550. a very popular mainstream AMD motherboard, you can find just that.
Here, the AMD B550 has CPU lanes conforming to V4.0 and the motherboard chipset lanes (aka general purpose lanes) conforming to V3.0.
Therefore, on a B550 motherboard if an M.2 SSD slot is connected to the CPU PCIe lanes, it would conform to V4.0. On the other hand, if it is connected to the chipset, general purpose, lanes it would conform to V3.0.
With AMD X570, however, both CPU and motherboard chipset lanes conform to V4.0. Hence all M.2 SSD slots on this motherboard will be V4.0 and thus capable of supporting 4.0 PCIe SSDs to their max potential.
Motherboard Chipsets That Support V4.0 SSDs
The motherboard is the primary aspect that determines the PCIe version of the M.2 slot.
Currently both AMD and Intel have motherboards that do support 4.0 PCIe SSDs.
For AMD, the following chipsets support 4.0 SSDs:
- AMD X570: Premium Chipset with both CPU and Chipset lanes conforming to V4.0.
- AMD B550: Mid Range Chipset with only the CPU lanes conforming to V4.0.
Intel has several chipsets from 500 and 600 Series at the moment that can support 4.0 SSDs.
From the 500 Series we have:
- Intel Z590: Premium Chipset – but only CPU lanes conform to PCIe V4.0 – hence it can only support a single V4.0 M.2 slot.
- Intel B560: A mid range chipset with support for a single V4.0 M.2 slot
- Intel H570: Another mid range chipset with support for a single V4.0 M.2 slot.
From the 600 series we have:
- Intel Z690: Premium Chipset – but only CPU lanes conform to PCIe V4.0
- Intel H670: Like Z690 but not overclockable
- Intel B660: Mid range with CPU lanes conforming to PCIe 4.0
AMD X570 – The Most Superior Chipset for V4.0 SSDs
AMD X570 stands out the most from above, because this is the only chipset with both CPU and general purpose lanes conforming to PCIe v4.0.
Hence, all the M.2 slots on this motherboard would be able to support 4.0 PCIe SSDs.
With the rest of the chipsets (at the moment), only the M.2 slots connected to CPU lanes support V4.0 PCIe SSDs, which is often only one slot in most cases.
Also Read: How to Add More M.2 SSD Slots?
The Choice of CPU Matters!
Currently, the AMD 3000, 5000, 6000, 7000 and Intel 11th Gen Onwards processors support PCIe v4.0 protocol.
Additionally, for the AMD 3000 and 5000 series CPUs, only the non-G series processors support V4.0 i.e AMD Ryzen 3300X does support PCIe V4.0; AMD Ryzen 3400G DOES NOT.
There are huge caveats on motherboard specifications sheets and manuals that tell you exactly which M.2 slots conform to PCIe V4.0 and the CPU’s required to power it.
For instance, the image below shows an excerpt of specifications for ASUS PRIME H570-PLUS.
This motherboard supports 2 x M.2 slots.
The first M.2_1 slot conforms to PCIe 4.0, HOWEVER, it ONLY WORKS at V4.0 if you have an 11th gen Core Series processor connected. Otherwise it would get disabled.
The second M.2_2 slot connects to the Intel H570 chipset lanes and therefore only works at PCIe v3.0.
Also Read: Does SSD Improve Gaming Performance?
Can PCIe 4.0 SSD Work in 3.0?
Yes, a PCIe 4.0 SSD such as the Samsung 980 Pro can work on a V3.0 M.2 slot. HOWEVER, the performance of the Gen 4 SSD can be reduced by as much as half its optimal performance.
Is M.2 PCIe 4.0 Slot Backward Compatible?
Yes, if your motherboard has an PCIe 4.0 M.2 slot, then you can most certainly plug in an older Gen 3/PCIe 3.0 NVMe SSD. There will be no performance issues or compatibility issues at all.
Does B550 Support Gen 4 SSD?
Yes, AMD B550 motherboards do support gen 4 SSDs. B550 motherboard support 16 V4.0 PCIe lanes for the x16 PCIe slot, and 4 PCIe V4.0 lanes for an M.2 slot.