[SOLVED] Will this build have enough PCI-e lanes / bandwidth ?

brokeBuilder2019

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I'm planning a new video editing PC build, and am confused about the CPU / Chipset PCI-e lanes and how contention / shared bandwidth affect the speed of PCI-e components.

I list my build below (relevant components only). Please point out if any of my PCI-e components will run below their max potential bandwidth / speed as a result of bandwidth sharing with other components. In other words, will this build provide enough bandwidth for all my components or do I have too many PCI-e components in my build ?

MSI MEG Unify X570 AM4 motherboard
AMD Ryzen 9 5950X 16-Core 3.4 GHz Socket AM4 105W Processor

Storage
-----------
WD Black 500GB PCI-e 4.0 x4 NVMe SSD
WD Black 2TB PCI-e 4.0 x4 NVMe SSD
Sabrent Rocket 8TB PCI-e 3.0 x4 NVMe SSD
------------

Graphics and sound
-------------------------
MSI GeForce RTX 3080 PCI-e 4.0 x16 GPU
Creative SoundBlaster AE-7 PCI-e 3.0 x1 sound card

My CPU provides 20 lanes, and my X570 chipset provides 16 lanes, for a total of 36 usable lanes.
And, from my calculations, my components require a total of (4 * 3) + 16 + 1 = 29 lanes.
Does this mean that there will be no bandwidth sharing or slowdowns due to "contention" ?
 
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Storage
-----------
WD Black 500GB PCI-e 4.0 x4 NVMe SSD
WD Black 2TB PCI-e 4.0 x4 NVMe SSD
Sabrent Rocket 8TB PCI-e 3.0 x4 NVMe SSD
------------
....
Ryzen 5000 CPU's provide 4 dedicated gen 4 lanes for one NVME and 16 dedicated gen 4 lanes for one GPU. Be sure to use the right slot for the GPU and it gets all 16 of dedicated PCIe lanes provided by the CPU. According to the board's specification sheet it supports 2 M.2 PCIe x4 gen 4 NVME fed from the chipset in addition to the 1 M.2 PCIe x4 gen 4 fed from the CPU, with no notes or bullets about lane sharing. You should be good to go with no significant contentions in that configuration, as it should be with an X570 chipset and Ryzen 5000 CPU.

Some things to keep in mind:
1)The M.2 and PCIe x16 slots closest to the CPU will be the ones that are fed directly by the CPU. I'd use those for the system drive and GPU so that they have the lowest latency for best system performance.
2)Installing your Soundblaster in some of the remaining PCIe slots will disable one of the other slots. That shouldn't be a problem unless you come along with another PCIe device. Not a real problem, just be ready to go for another slot if the first choice doesn't work and it should only arise if you want to add a third PCIe device.
 
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Storage
-----------
WD Black 500GB PCI-e 4.0 x4 NVMe SSD
WD Black 2TB PCI-e 4.0 x4 NVMe SSD
Sabrent Rocket 8TB PCI-e 3.0 x4 NVMe SSD
------------
....
Ryzen 5000 CPU's provide 4 dedicated gen 4 lanes for one NVME and 16 dedicated gen 4 lanes for one GPU. Be sure to use the right slot for the GPU and it gets all 16 of dedicated PCIe lanes provided by the CPU. According to the board's specification sheet it supports 2 M.2 PCIe x4 gen 4 NVME fed from the chipset in addition to the 1 M.2 PCIe x4 gen 4 fed from the CPU, with no notes or bullets about lane sharing. You should be good to go with no significant contentions in that configuration, as it should be with an X570 chipset and Ryzen 5000 CPU.

Some things to keep in mind:
1)The M.2 and PCIe x16 slots closest to the CPU will be the ones that are fed directly by the CPU. I'd use those for the system drive and GPU so that they have the lowest latency for best system performance.
2)Installing your Soundblaster in some of the remaining PCIe slots will disable one of the other slots. That shouldn't be a problem unless you come along with another PCIe device. Not a real problem, just be ready to go for another slot if the first choice doesn't work and it should only arise if you want to add a third PCIe device.
 
Last edited:
Reactions: brokeBuilder2019

brokeBuilder2019

Prominent
Sep 14, 2019
77
15
545
4
Ryzen 5000 CPU's provide 4 dedicated gen 4 lanes for one NVME and 16 dedicated gen 4 lanes for one GPU. Be sure to use the right slot for the GPU and it gets all 16 of dedicated PCIe lanes provided by the CPU. According to the board's specification sheet it supports 2 M.2 PCIe x4 gen 4 NVME fed from the chipset in addition to the 1 M.2 PCIe x4 gen 4 fed from the CPU, with no notes or bullets about lane sharing.

You should be good to go with no contentions in that configuration, as it should be with an X570 chipset and Ryzen 5000 CPU.
Awesome, thanks for confirming this ! Cheers :)
 

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