SSD storage expansion on B550M but only x1 mode PCIe slots available

Question

I have a Gigabyte B550M Gaming MOBO. Here's a cropped screenshot of my MOBO from official site.

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And here's the MOBO specification for the slots.

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Right now, the ONLY (sadly) M.2 connector is occupied by my PNY CS1031 M.2 NVMe SSD 256GB, this is where my system drive currently is. And then, there are two unused PCIE x1 slots that support PCIe 3.0 x1 mode. Here's the problem, I was planning to expand my SSD storage by adding a Samsung 980 M.2 NVMe SSD 1TB with a M.2 to PCIe adapter. Later only found out that an adapter like this it has to be x4 mode, which essentially renders the PCIe slots on my MOBO practically useless for storage expansion. Is it true?

Now, my intention to expand SSD is mainly to install game files. Presuming the above is true, here are my options:

1. Replace the current M.2 NVMe SSD that I have, which means I have to swap them out and let the old one go unused and wasted. Not to mention I have to do system drive migration as well.
2. Give up on M.2 NVMe SSDs and go for SATA SSDs instead.

My friend urged me to go after M.2 NVMe SSDs and we both know they are much better than SATA SSDs. Can I get some advice on my options available? How should I make the decision? Because I'm not convinced enough to get SATA instead. It's almost 2022, is it even worth it based on the price-to-product ratio? What's the difference between the M.2 NVMe and SATA SSDs in terms of performance?

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These are some of the products I get from a reputable IT retailer store in where I live, for your reference. Prices are converted from my local currency to USD. Upcoming sales.

SATA(s)

• Samsung 870 Evo 2.5" SATA SSD 1TB ~ $173
• Samsung 870 Qvo 2.5" SATA SSD 1TB ~ $104
• Crucial MX500 2.5" SATA SSD 1TB ~ $92
• Crucial BX500 2.5" SATA SSD 1TB ~ $85

M.2 NVMe(s)

• Samsung 980 M.2 NVMe (Gen 3) SSD 1TB ~ $135
• PNY CS3040 M.2 NVMe (Gen 4) SSD 2TB ~ $213
• Crucial P1 M.2 NVMe (Gen 3) SSD 2TB ~ $201
• Crucial P2 M.2 NVMe (Gen 3) SSD 1TB / Kingston A2000 NVMe SSD 1TB ~ $101

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Further reference (case study): Hardware Recommendations - M.2 NVMe x4 adapter card for PCIe x1 slot

Answer 1

NVMe storage is a protocol built on top of PCIe; And PCIe has always been able to negotiate the number of lanes used based on what's physically connected.

You probably already know that a x1 PCIe device in a x16 slot still connects and only uses 1 lane even though the slot has 8 or 16.

The opposite works too! A x16 PCIe device in a x1 slot still connects and works just fine at 1/16th of the bandwidth. (Of course you need to modify the connector to make it fit)

When it comes to M.2 slots it's the same deal. There are lots of x2 M.2 drives out there, also lots of M.2 ports with only x2 lanes wired up to them. The NVMe SSD will still connect over any PCIe link that is physically available because of that dynamic negotiation of how many PCIe lanes are used.

Knowing this, there isn't a technical reason you can't use NVMe over a x1 PCIe connection unless the SSD itself is cutting corners and not implementing a fully compliant PCIe device. (And of course there are definitely SSDs out there you should avoid with these adapters.)

x1 PCIe adapters for M.2 slots do exist!

Go ahead and try one of these adapters. It's a very low cost to pay for finding out if your current SSD works in it. If it works you can feel safe buying another M.2 SSD because you know the one you already have works in the adapter and the M.2 on the motherboard would be free.

Answer 2

Since you are mostly going to use it for game files, SATA is more than enough. As a general rule of thumb, you want an SSD with DRAM cache (so no BX500) and no QLC (no Samsung 870 QVO). The cheapest option (and from my experience also a good option) is the Crucial MX500 1TB.