# Nvme PCIe 4.0 M.2 and Nvme PCIe 3.0 M.2



## speedpc (Jul 4, 2020)

Hello Everyone, Hopefully this can be an easy question:  So i built my Son a new PC for graduation, MSI X570 Tomahawk with a 3900X , I put in a 1TB  Nvme *PCIe 4.0 *M.2 ssd with Windows 10 and some of his games,  So now he went out and bought a 1TB Nvme *PCIe 3.0* M.2 ssd for more games. Will running the the *PCIe 4.0* ssd and the *PCIe 3.0* ssd cause any issues on the same motherboard ??? Mainly will it slow down the performance of the Nvme PCIe4.0 ssd? Any feedback would be appreciated Thank You


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## er557 (Jul 4, 2020)

i believe everything would work normally, same as multiple pcie cards at different rates, one should not contradict the other, as the chipset and cpu have multiple lanes, you decide how they are spread out.


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## Caring1 (Jul 5, 2020)

The top M2 slot should be wired PCIe-4
The lower slot should be PCIe-3
The manual should show you the layout.


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## TheLostSwede (Jul 5, 2020)

No, no issues, the second drive will simply run in PCIe 3.0 mode.
The top-most slot is also connected to the CPU, while the second one is connected to the chipset, so there's no interaction in that sense that would cause problems either.



Caring1 said:


> The top M2 slot should be wired PCIe-4
> The lower slot should be PCIe-3
> The manual should show you the layout.


Huh? It's X570, not B550...
Nor is it one of the gimped MSI boards.


> 2x M.2 slots (Key M) 1
> 
> M2_1 slot (from AMD® Processor)
> Supports PCIe 4.0 x4 (3rd Gen AMD Ryzen™)
> ...








						MAG X570 TOMAHAWK WIFI | RETURN TO HONOR
					

Military style with Pre-installed IO shielding, tuned for better performance by Core Boost, DDR4 Boost, M.2 Shield Frozr, Wi-Fi 6, Frozr Heatsink Design, Lightning Gen4




					www.msi.com


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## speedpc (Jul 5, 2020)

Thanks Everyone, Much Appreciated


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## thesmokingman (Jul 5, 2020)

That's a pretty kick ass system for your kid.


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## PCMcGee (Jul 20, 2020)

Caring1 said:


> The top M2 slot should be wired PCIe-4
> The lower slot should be PCIe-3
> The manual should show you the layout.


Sorry if I am misinformed but, from what I understand the top m.2 PCIE slot is coming from the processor, and the videocard being PCIE 3.0 will cause the bus to use the lowest setting available for the devices attached. It seems like using the chipset bus for the PCIE 4.0 device would enable the PCIE 4.0 M.2 drive to operate at full PCIE 4.0 speed, where if it was attached to the CPU bus it would throttle back to the GPU's speed of PCIE 3.0. (The chipset bus on the X570 also runs PCIE 4.0)

I am building a system that would have almost identical issues, and this is what I have been led to believe.


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