[SOLVED] PCIe speeds for a SATA Controller

[davidst95]

Hi, I'm looking at getting a H200 6Gb PCI-e SAS SATA 8-Port Raid Controller in IT Mode for FreeNAS. 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 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

 

[kanewolf]

Don't hold your breath for 2.5 or 5Gb/s ethernet. I have been very disappointed in the availability of devices.
You can do the math -- According to the Wikipedia page you get 500MB/s on a PCIe 2.0 lane. So x4 has 2GB/s theoretical performance. If you have 8 SSDs on that controller their performance will be hurt. But since you are using this as a NAS with 1Gb/s (110MB/s) performance you probably won't see any issues. Your network will be the limiting factor.

 

[davidst95]

Thanks for the info. I was planning on 4 10TB Red 5400 RPM drives and 2 SSD for cache.