[SOLVED] SAS Controller for my Asus Z97-C board

[Juli]

Hey guys,

 

I'm just recycling my old desktop as an unraid NAS. I'm looking for an fitting SAS controller, but I'm not sure which one would work with my pcie ports . Probbaly someone could explain or recommend a bit. Here is the manual of my board.

It states:

Quote

1 x PCI Express 3.0/2.0 x16 slot (at x16 mode)

1 x PCI Express 2.0 x16 slot* (max. at x4 mode, compatible with PCIe x1 and x4 devices)

2 x PCI Express 2.0 x1 slots*

3 x PCI slots

* The PCIe x1_1, PCIe x1_2 slots share bandwidth with PCIe x16_2(@x4).

The PCIe x16_2 slot runs at x2 mode as default. Please check BIOS for more configuration.

If I can see it right. If I have my RTX 2060(want to use it for passthrough vm) in it which is set into the 1 x PCI Express 3.0 slot it covers all ports except the 1 x PCI Express 2.0 x16 and 2 normal PCI slots. The storage controllers I checked online Adaptec ASR-71605(needs PCI E 3.0) and LSI Megaraid 9201-8i 6G PCIe 2.0 x8 SATA/SAS HBA(needs PCI E 2.0 x8) won't work with the RTX in the system, right? I'm a bit confused with the * stuff in the manual. So are there proper alternatives?

 

Thanks in advance,

Juli

Edited June 5, 2020 by Juli

[JorgeB]

HBA should work fine on the x4 slot, with limited bandwidth.

[Juli]

3 minutes ago, johnnie.black said:

HBA should work fine on the x4 slot, with limited bandwidth.

Ok. What do you mean by limited bandwidth?

[JorgeB]

It will link at x4 instead of x8, but it might be a non issue depending on how many and what type of devices you will have there.

[Juli]

2 hours ago, johnnie.black said:

It will link at x4 instead of x8, but it might be a non issue depending on how many and what type of devices you will have there.

So basically PCI-e 2.0 has about 0.5 GByte/s per lane. The controller wants to have x8(for its max workload) that would be 4 GByte/s and with the x4 mode its 2 GByte/sec which should be fast enough for my HDDs. Ok thanks. I think I got it. I will get the LSI Megaraid 9201-8i 6G PCIe 2.0 x8 SATA/SAS HBA

[JorgeB]

12 minutes ago, Juli said:

x4 mode its 2 GByte/sec which should be fast enough for my HDDs.

Correct, about 1600MB/s usable due to PCIe overhead, still enough for most spinners, even with all ports in use.