QUESTION: Bandwidth on SlimSAS

Hey Gang,

Question - what kind of bandwidth can you get on SlimSAS on the SuperMicro H12SSL-NT MOBO using the SuperMicro CBL-SAST-0827 cables?

Looking to build some media storage to eventually phase out our Promise Pegasus32 R8 units with TrueNas-based system.


PCIe Gen4 with Rome or Milan EPYCs.

Getting “good” cables on the other hand has been the Bane of my DIY home server existence for over a year now (still unsuccessful, I don’t consider connected devices to just run with PCIe Gen4 a success, I don’t want any PCIe Bus Errors) - for more details refer to this thread:

I think you are living on another planet @aBav.Normie-Pleb cause I can’t for the life of me figure out how that has anthing to do with my question? LOL :innocent:

Oh sorry, I didn’t even think of not using the ports for PCIe!

You can get around 560-570 MB/s (that’s the best I’ve ever seen with Samsung 860 PRO SATA SSDs) per drive port with the fastest SATA SSDs :stuck_out_tongue:

Since every connection goes directly into EPYC’s SoC you don’t have any chipset interface bottlenecks.

Ok, I know the bandwidth of the SSD devices - but the question is the SlimSAS bandwidth via the cable my friend!

These ports don’t come from a SAS controller, you can only choose between SATA/AHCI and PCIe/NVMe.

It’s only the physical connector on the motherboard end that is called “SlimSAS”.*

When using them for SATA 3 just multiply the number of drive ports with 6 Gb/s.

*There sometimes are motherboard variants that have a proper SAS controller chip onboard as an additional feature, but not the model you’ve refered to.

So you know that 8 drives on this cable will support 8x6Gbs or you are speculating?

That’s the whole point of these break-out cables, yes. With SlimSAS 4i you can use 4 drives individually, with Slim SAS 8i you can use 8.

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