ROG Strix B350: M.2 disables SATA Ports 5 and 6?

[LightninBoy]

Short version: Can anyone confirm that using the M.2 input in PCIE mode will disable SATA ports 5 and 6? This is expected behavior for the ROG Strix B350 board?

Long version:

I just built a computer with the following core components:

AMD Ryzen 1600
ASUS ROG Strix B350 Gaming
Samsung 960 Evo NVME M.2 (250GB)
ASUS GTX 1060
GSkill DDR4 2400 (2x8GB)
Couple HDDs, DVD reader/writer, etc

Put it all together and right off the bat the DVD Reader/Writer doesn't work. Eventually I observed that the BIOS wasn't recognizing it, and after some more troubleshooting I narrowed it down to SATA ports 5 and 6 not recognizing anything that I plugged in and the DVD Reader/writer just happened to be plugged in to SATA 5 to begin. At this point I'm thinking I might have a faulty motherboard, but maybe there's some BIOS setting I'm missing. Alright ... to the internet!

Some internet research quickly brought me to posts about other motherboards that disable SATA ports when the M.2 input is used. I scoured the manual once again looking for some indication of this behavior in the ROG Strix B350. I found only this buried in a footnote in the Specifications list: "When a SATA mode M.2 device is installed, the M.2 socket shares bandwidth with the SATA 5/6 ports". Note, this only mentions "SATA mode". However, my M.2 device (the 960 evo) works in PCIe mode. Also, it doesn't really say the ports are disabled, just that the bandwidth is shared.

I downloaded an updated manual from the Asus site. This also makes no mention of the SATA ports being disabled. However, next to the above footnote, it adds the following: "When a SATA / PCie mode M.2 device is installed, the M.2 Socket shares bandwidth with the SATA 5/6 ports". So now it includes PCie mode too, but still only says that bandwidth is "shared".

So what I'm looking for is confirmation this it is expected behavior for SATA ports 5/6 to be completely disabled when the M.2 socket is used regardless of whether it is in SATA or PCIe modes. Thanks!

[Chino]

*5 When a SATA / PCIE mode M.2 device is installed, the M.2 Socket shares bandwidth with the SATA6G_5/6 ports.

https://www.asus.com/Motherboards/ROG-STRIX-B350-F-GAMING/specifications/

[LightninBoy]

Uh yeah. I referenced that in my post. But "shares bandwidth" is not the same as "completely disables", so I'm still looking for someone to confirm that it is normal and expected behavior for ports SATA 5 and 6 to be completely disabled when the M.2 port is used.

[Bill]

Hello LightninBoy
I'll consult our team about this
I'll get back to your once I got more information
Thank you

[LightninBoy]

I don't understand. How can there be pages and pages of information about overclocking but something as simple as this question cannot be answered? This is fundamental behavior that a builder needs to know while choosing components. And to avoid wasting time troubleshooting components if they happened to be plugged into SATA ports 5 and 6.

If it is true that SATA ports 5 and 6 are disabled when the M.2 port is used then it has to be clearly documented - not buried in a footnote and then euphemistically saying "shares bandwidth with" instead of "disables".

[bmac1191]

Sata uses pcie lanes so I would assume the answer is yes - it does disable them. It seems you have confirmed it.

I was searching for the same thing. I am building a rig with a b350m-a and noticed the same wording which doesn't make sense. If you need the two sata ports, you'll have to get a x370 board.

Just found a more detailed notation on my board's page..

3*The M.2 Socket shares bandwidth with the SATA6G_5/6 ports, therefore the SATA6G_5/6 ports cannot be used when a SATA/PCIE mode M.2 device is installed

[LightninBoy]

Many thanks. That is helpful.

[Darrenuk]

LightninBoy wrote:
Many thanks. That is helpful.

Yep, it disables SATA ports 5 & 6, Just installed a 960 Evo M.2 & don't detect HDDs when M.2 is Used, They should add this like you say to the Online Info.

[Turkmonkie]

Darrenuk wrote:
Yep, it disables SATA ports 5 & 6, Just installed a 960 Evo M.2 & don't detect HDDs when M.2 is Used, They should add this like you say to the Online Info.

Seams like I have the same problem. moving HDD to port 1 or 2 SATA fix the issue?