Asrock Rak C3758D4I-4L: Total 3gbs SATA with 10gbe card?

With the Asrock Rack C3758D4I-4L it looks like any 10gbe card I use will take at least 4 lanes and according to it's manual, it will drop the SATA capacity to 9, but that is in 6gbs. I'm wondering if I can I keep the onboard 5 SATA at 6gbs, and put the 8 SAS at 3gbs so I can squeeze in a 10gbe card and have at least 11 SATA connections. The manual doesn't mention this so I have to assume no, but that might not be definitive.

The board looks really good, but since that Atom only has 16 lanes... not so good. The only other option I see would be to go with an embedded EPYC and that literally doubles the cost for which would be essentially for keeping only 2 drives off of USB.

Quote from gderf

What are your expectations / use case for the 10gbe card?

I've decided to not worry about the 10gbe. It's just that I have 2 x520's somewhere for a poor man's CouchDB project, but since I never used them anyhow :-/ (would be nice to future proof though).

What is the part number of your breakout cable that you're using with that SAS card?

I actually looked for your board and the 2750 variant, but they aren't easily found anymore. I found a couple with bad VGA or unknown power problems, but that was it (so they seem to be desired).

I'll probably wind up with a X570D4U-2L2T which happens to have 10gbe, but it takes a warmer Ryzen and it's a big micro atx board, so maybe not :-/. If you have any sources for your board or other suggestions let me know. Right now it's between that x570 and the c3758.

It's turning out to be one of those things were I can't have it all. All the stars NEARLY come aligned, but there's just that 1 thing! Even the pricier $800+ embedded epyc's don't have a lot of SATA ports and those large expansive SAS cards are high $$$$. However, your board looks amazing so it gives me hope :-).

EDIT: I just looked up these SAS cards used, they are not high dollar.

I found 2 e-mails, 1 is a daemon failure and I guess the other sent, so hopefully sometime tomorrow I will know.

No matter what, I'll have to e-mail somewhere there as I'm not sure if I'm reading the C3758 correctly as far as lanes. I know the CPU has 16 lanes, but what I can't tell is how many the 2 mini SAS headers use, and the manual is starting to sound like if 8x is desired on the PCIe header, then that is when and only when you loose 4x lanes.

Also, how many lanes do these SAS adapters use? I see a 8 lane PCIe 2.0 card with 16 SAS/SATA connections. It has a little battery for something... https://www.ebay.com/itm/LSI-Megaraid-SAS-9260-16I-SAS-512MB-Controller-L3-25243-20D-W-BATTERY-CABLES

To state that I was wrong and possibly for future users, this board will drop 1 of the mini sas ports if the PCI header is running at 8x, leaving 9 available SATA ports. My mistake was that I inverted the logic so I read it as if it was removing 8 ports, not how many will remain.

I"m not going to buy a 10gbe card or SAS card, but thank you for the SAS recommendation, I bookmarked it (and I still might buy it... I got an itch).

From the manual (FWIW, the 3558 looks puzzling bad):

C3758D4I-4L
Config 1: PCIE7 x8, SATA_0-7
Config 2: PCIE7 x4, SATA_0-12

C3558D4I-4L
Config 1: PCIE7 x4, SATA_0-3 and 12
Config 2: PCIE7 x4, SATA_4-7
Config 3: PCIE7 x4, SATA_8-12
Config 4: PCIE7 x8, SATA_12
Config 5: SATA_0-7 and SATA_12
Config 6: SATA_4-12
Config 7: SATA_0-3 and SATA_8-12