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PCIe Lanes for Ryzen ..

Hey, I have few questions. 

1) I was looking in Ryzen CPU a while back and i don't know exactly how many PCIe lanes it has ... Maybe 24 PCIe lanes (16 Gen3 lanes from the cpu and 8 Gen2  lanes from the chipset of x370 mobo ?  

 

2) How many PCIe lanes does M.2 NVMe SSD takes in M.2 slot and which Gen ? ///////////

 

Because i was kinda wondering since im trying to build computer, like graphics will requier x16 lanes and from and that's ok... but from then on idk for M.2 NVMe SSD, if it will requier 2 pcie lanes (Gen2) or 4 pcie lanes as gen3 ....

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The Ryzen chips themselves deliver 24 PCIe 3.0 lanes directly and then additional lanes will come from the chipset for other peripherals.

 

M.2 drives generally take 4 PCIe 3.0 lanes. GPU's will function without any noticeable performance impact at x8 on 3.0 slots so you're fine there.

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2 minutes ago, Lurick said:

The Ryzen chips themselves deliver 24 PCIe 3.0 lanes directly and then additional lanes will come from the chipset for other peripherals.

 

M.2 drives generally take 4 PCIe 3.0 lanes. GPU's will function without any noticeable performance impact at x8 on 3.0 slots so you're fine there.

so that mean that i can make crossfire 1x16/1x8 with GPUs and then since all 24 lanes are used by GPUs. So then I can plug in M.2 slot 1 NVMe SSD because it will take lanes from chipset...(because i assume that this 8 lanes from chipset are actually gen2 which is 4pcie lanes gen3, if not correct me).... But I still don't know if pcie lanes from chipset of x370 mobo are gen3 or gen2... like if we get 8 pcie lanes gen3 then we are in heavens =P

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According to this:

14878984098.gif

 

You've got a dedicated x4 of PCIe Gen 3 for the M.2 drive.

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10 minutes ago, Lurick said:

According to this:

14878984098.gif

 

You've got a dedicated x4 of PCIe Gen 3 for the M.2 drive.

so together they will gave u 24 gen3 pcie lanes right ? 

 

then i could still run 1 gpu at speed of 16x speed + 1 nvme ssd since i wont use anything else or am i wrong again ? ._. 

 

like then 8lanes from cpu will remain and i don't see problem why i couldn't do so and as well im kinda new in this and i don't kinda understand everything yet so don't be angry :@

 

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3 minutes ago, Klemen said:

so together they will gave u 28 pcie lanes right ? 

 

then i could still run 1 gpu at speed of 16x speed + 1 nvme ssd since i wont use anything else or am i wrong again ? ._. 

 

like then 8lanes from cpu will remain and i don't see problem why i couldn't do so and as well im kinda new in this and i don't kinda understand everything yet so don't be angry :@

 

You can run 2 GPUs (2 8x) and an NVMe SSD using the CPU lanes without touching the chipset lanes.

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5 minutes ago, tom_w141 said:

You can run 2 GPUs and an NVMe SSD using the CPU lanes without touching the chipset lanes.

well yeah since 2xgpus x8/x8 + 4 pcie lanes from nvme =20pcie lanes but isnt it like that, that ssd should take lanes from PCH instead of cpu lanes ? or is this rule only for audio cards etc... ? 

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Just now, Klemen said:

well yeah since 2xgpus x8/x8 + 4 pcie lanes from nvme =20pcie lanes but isnt it like that, that ssd should take lanes from PCH instead of cpu lanes ? 

Devices will take CPU lanes when available as they are faster.

 

You can have on the CPU:

1 GPU (x16) 1NVMe

or

2 GPU (2 x8) 1NVMe

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1 minute ago, tom_w141 said:

Devices will take CPU lanes when available as they are faster.

 

You can have on the CPU:

1 GPU (x16) 1NVMe

or

2 GPU (2 x8) 1NVMe

I get that but CPU will allow me only 20 lanes and PCH additional 4 right ? 

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or it would belike if i keep PCIe lanes in PCH I will have higher bandwidth. mabye it sounds svery stupid but im just curious ;P

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5 hours ago, Klemen said:

I get that but CPU will allow me only 20 lanes and PCH additional 4 right ? 

Ryzen CPUs have 20 lanes for general use, and an additional 4 lanes dedicated to the PCH which cannot be used for anything else such as graphics cards. It will not be possible to run triple graphics cards at ×8/×8/×8.With 20 lanes, you can run at most one graphics card at ×16 or two graphics cards at ×8/×8 with a PCIe 3.0 ×4 M.2 SSD simultaneously.

 

The PCH lanes are used for the functions of the PCH, allowing all USB ports and SATA ports to communicate with the CPU, ethernet, and all other low-speed I/O, as well as auxiliary PCI Express lanes (8 PCIe 2.0 lanes) which are used by the motherboard manufacturer at their discretion, usually to add additional I/O beyond what the PCH supports natively, and for all the PCIe 2.0 ×1 slots.

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