PCIe SATA Controller Speed Imapct

[davidst95]

Hi, I'm rethinking my new FreeNas Setup.   I'm looking at a H200 6Gb PCI-e SAS SATA 8-Port Raid Controller in IT Mode for a FreeNas VM hosted with ESXi.   It fits into a PCIe x8 slot running at PCIe x8 2.0.   My motherboard only has a free slot that's PCIe x8 but only at PCIe x4 2.0 speed.   Will this slower slot affect transfer speeds if I also have SSD cache drives?   I only have a 1 GB/s network but plan on upgrading my network to 2.5 GB/s or 5GB/s in the near future.  Thanks!

 

David

[davidst95]

1 hour ago, davidst95 said:

Hi, I'm rethinking my new FreeNas

 

[Olaf6541]

PCIe x4 2.0 is 16Gb/s of bandwidth so even with 2.5Gb/s or 5Gb/s that wont be an issue.

[davidst95]

10 hours ago, Olaf6541 said:

PCIe x4 2.0 is 16Gb/s of bandwidth so even with 2.5Gb/s or 5Gb/s that wont be an issue.

Thanks for the reply. I read online that PCIe 2.0 X4 is only 2G/s a second.  I assume this would slow down a SATA 3.0 6Gbs connection.  I'm probably not understanding something correctly.  Thanks again for the info. 

 

https://www.gamersnexus.net/guides/2488-pci-e-3-x8-vs-x16-performance-impact-on-gpus

[Olaf6541]

7 hours ago, davidst95 said:

I read online that PCIe 2.0 X4 is only 2G/s a second.

16Gbit/s is 2Gbyte/s (1 byte is 8 bits). That should explain it.