PCIe 1x Bandwidth Question w/4 Port Card

[Skram0]

If I install a PCIe 1x SATA card that has 4 ports and use all ports with 7200 RPM drives in one raidz vdev, would I end up saturating the PCIe 1x bandwidth? I've read the bandwidth is 250MB/s either read or write, and 500MB/s while reading and writing at the same time.

I've seen my system transfer at more than 100MB/s when I copy a file from drive to drive. So if I have a 4 drive RAID-Z going on, and it's reading from all drives at the same time, would that saturate the 250MB/s read limit from the PCIe 1x bus? If so, I'm guessing using 2 2-port 1x cards would be better.

EDIT: Well I may have found my answer. I guess those speeds are for PCIe 1.0. And PCIe 2.0 is 500MB/s each direction, and 3.0 is 985MB/s each direction. So the motherboard I'm looking at has 1 PCIe 2.0 x16 and 1 PCIe 3.0 x16. I should be able to use the x1 card (as long as it is compatible with PCIe 2.0+) in the 2.0 x16 slot and still be okay for bandwidth. Are the low-end Highpoint cards okay? The ~$40 models?

 

[jgreco]

Tackling this from a different angle:

1) ZFS is kind of slow and piggy and you're simply not likely to run into a problem because you're not too likely to get 500MB/sec moving around very easily.

2) If you manage to stick a rocket up ZFS's tailpipe, you're still going to be limited by 1GbE network connections (~120MB/sec at best).

I seem to recall some griping about Highpoint cards though.