What is the Difference Between the Two and Three Port NvME Disks?

The question about “2-port and 3-port NVMe disks” is a bit of a misnomer in common consumer terminology. NVMe (Non-Volatile Memory Express) is a communication protocol designed specifically for SSDs to leverage the high speed of the PCIe (Peripheral Component Interconnect Express) interface.

What you’re likely referring to when you mention “ports” is actually related to:

1. PCIe Lanes (x2, x4, etc.): This is the most common way to describe the “port” aspect of NVMe drives. PCIe works with “lanes” that transmit data.
   • x2 NVMe drive: This refers to an NVMe SSD that uses 2 PCIe lanes. This will offer good performance, but less than a drive using more lanes.
   • x4 NVMe drive: This refers to an NVMe SSD that uses 4 PCIe lanes. This is the most common configuration for high-performance consumer NVMe SSDs and offers significantly higher speeds than x2, as it has double the bandwidth.
2. M.2 Slot Keying: M.2 is a form factor for SSDs, and M.2 slots have “keys” that dictate which interfaces they support.
   • B-key: This can support SATA and PCIe x2.
   • M-key: This can support SATA and PCIe x4.
   • B+M key: This is a universal key that fits in both B and M keyed slots, but its performance will be limited by the slot’s capabilities (e.g., if plugged into a B-keyed slot, it will operate at PCIe x2).

Therefore, when you say “2-port” or “3-port” NVMe disks, you’re likely thinking about:

• “2-port” might refer to an NVMe SSD that utilizes 2 PCIe lanes (x2). These are less common for modern high-performance drives but can be found, especially in some older or budget-oriented systems where motherboard lanes are limited.
• “3-port” is not a standard term for NVMe drives. It’s possible you might be thinking of something like:
  • A system with three M.2 slots: Many motherboards have multiple M.2 slots, each supporting NVMe drives (typically x4). The specific performance of each slot can vary, with some sharing bandwidth with other components (like SATA ports or other M.2 slots).
  • M.3 form factor (NGSFF): This is an enterprise-focused form factor that is larger than M.2 and can offer higher capacities and features, but it’s not a consumer standard and wouldn’t be described as “3-port” in the way you’re asking.

Key Differences (focusing on PCIe lane count, which is the most probable interpretation of your question):

Export to Sheets

In summary, the number of “ports” for an NVMe disk typically refers to the number of PCIe lanes it utilizes (e.g., x2, x4), which directly impacts its maximum theoretical speed. “3-port” isn’t a standard specification. If you’re encountering the term “3-port,” it might be a misunderstanding or referring to something else entirely, like the number of M.2 slots available on a motherboard. Sources

In Other Words the Contacts are Split Into Either Two or Three Parts on an M2 drive

You’re exactly right! When talking about M.2 drives and the “contacts being split into either two or three parts,” you’re referring to the keying of the M.2 connector, which dictates its compatibility and what kind of interface it uses.

Here’s a breakdown of what those “splits” or “notches” mean:

• M-key (one notch, in the “M” position on the right side of the connector when looking at the pins):
  • This key is primarily designed for PCIe x4 (4 lanes) connections.
  • This is what you want for high-performance NVMe SSDs. It provides the most bandwidth, allowing the SSD to reach its full potential.
  • An M-key slot on a motherboard is generally compatible with both M-keyed SSDs and B+M-keyed SSDs.
• B-key (one notch, in the “B” position on the left side of the connector when looking at the pins):
  • This key supports SATA and PCIe x2 (2 lanes).
  • You’ll typically find B-keying on M.2 SATA SSDs, which are slower than NVMe drives but often more affordable.
  • While it can support PCIe x2 NVMe, it’s less common for dedicated NVMe drives to be B-keyed, as it limits their performance.
• B+M key (two notches, one in the “B” position and one in the “M” position):
  • This is a universal key designed for maximum compatibility.
  • A B+M keyed SSD can fit into both B-keyed and M-keyed M.2 slots.
  • However, the performance of a B+M keyed SSD will be limited by the slot it’s plugged into.
    • If plugged into a B-keyed slot, it will operate at SATA speeds or PCIe x2 speeds (depending on what the SSD and slot support).
    • If plugged into an M-keyed slot, it will also be limited to SATA or PCIe x2 speeds, even though the M-keyed slot could support PCIe x4. This is because the SSD itself is designed for a maximum of PCIe x2 or SATA.
  • Many M.2 SATA SSDs are B+M keyed to make them compatible with a wider range of motherboards. Some older or lower-end NVMe drives that are PCIe x2 might also use B+M keying.

In essence:

• One “split” (M-key): Almost always indicates an NVMe SSD designed for PCIe x4 performance. This is the “faster” one.
• Two “splits” (B+M key): Indicates an SSD that can fit in more slots, but will typically be either a SATA SSD or a PCIe x2 NVMe SSD, meaning it will be slower than a full PCIe x4 NVMe drive.

So, while “2-port” and “3-port” aren’t the official terms, your intuition about the physical “splits” or “notches” is directly related to the underlying interface (SATA vs. PCIe) and the number of PCIe lanes (x2 vs. x4) that an M.2 drive can utilize, which ultimately determines its speed. Sources

here are examples of each – will both of these work in an older laptop?

To determine if both of these M.2 SSDs will work in an older laptop, we need to examine their specifications, particularly their keying and interface, and then consider what’s common for older laptops.

Let’s look at the images:

Image 1 (image_07beda.png):

• Label: “SATA SSD S201 512GB” and “M.2 2280 SATA SSD”
• Keying: Observe the notches on the connector. This drive has two notches (one on the left, one on the right, near the pins). This indicates a B+M key.
• Interface: This is explicitly a SATA M.2 SSD.

Image 2 (image_07bebb.jpg):

• Label: “fanxianxian / S501 256GB” and “M.2 2280 NVMe SSD”
• Keying: Observe the notches on the connector. This drive has one notch (on the right side, near the pins). This indicates an M-key.
• Interface: This is explicitly an NVMe M.2 SSD.

Compatibility with Older Laptops:

Here’s the crucial part for older laptops:

1. M.2 Slot Presence: First and foremost, the older laptop must have an M.2 slot. Many older laptops (e.g., from before 2014-2015) might not have one at all. They might only have 2.5-inch drive bays or mSATA slots.
2. M.2 Slot Interface (SATA vs. NVMe/PCIe): This is the biggest factor.
   • Older laptops that do have M.2 slots often support only M.2 SATA SSDs. The M.2 slot on these laptops is wired to the SATA controller.
   • True NVMe (PCIe-based) M.2 support is less common in older laptops. It became more prevalent from around 2015-2016 onwards, and even then, not all laptops with M.2 slots necessarily supported NVMe. Some early M.2 slots were only for SATA.
3. M.2 Slot Keying (B-key, M-key, B+M-key):
   • If the laptop’s M.2 slot is B-keyed or B+M-keyed, it likely supports M.2 SATA. An M.2 SATA (B+M key) SSD would fit physically and work, assuming the slot is wired for SATA.
   • If the laptop’s M.2 slot is M-keyed, it might support NVMe (PCIe) or it might still be limited to SATA speeds if the PCIe lanes aren’t fully implemented or activated in the BIOS. This is where it gets tricky with older machines. An M-keyed slot is a good sign for NVMe, but not a guarantee on older hardware.

Conclusion for your specific drives:

• Fanxiang SATA SSD S201 (Image 1 – B+M Keyed, SATA):
  • This drive is more likely to work in an older laptop if the laptop has an M.2 slot that supports SATA. Many older laptops that adopted M.2 first did so with SATA connectivity.
  • It will physically fit into both B-keyed and M-keyed slots, but its functionality depends on the slot’s interface support for SATA.
• Fanxiang NVMe SSD S501 (Image 2 – M-Keyed, NVMe):
  • This drive is less likely to work in an older laptop. For it to work, the laptop’s M.2 slot must specifically support NVMe (PCIe x4) and be M-keyed. This level of M.2 support (NVMe) was not common in “older” laptops. Even if the slot is M-keyed, it might still only be wired for SATA or PCIe x2, and not full NVMe.

Recommendation:

To know for sure, you need to:

1. Check the laptop’s specifications: Look up the exact model number of your older laptop. Search online for its M.2 slot specifications. Does it have an M.2 slot? If so, what interface does it support (SATA, PCIe GenX xY)? What is its keying?
2. Consult the laptop’s manual: The user manual will often detail the M.2 slot’s capabilities.
3. Physical Inspection (if possible and you’re comfortable): If you can open the laptop, look at the M.2 slot itself to see the keying (the notch position). However, the physical keying doesn’t always guarantee the interface support (e.g., an M-keyed slot could still be SATA-only on some older boards).

In summary: The SATA M.2 SSD (Image 1) has a higher chance of being compatible with an older laptop’s M.2 slot than the NVMe M.2 SSD (Image 2), primarily because older M.2 implementations often supported SATA before NVMe became widespread.

So are you saying that one notch = SATA and two notches = NvME

No, that’s not what I’m saying, and it’s a common point of confusion! Let’s clarify this directly.

Here’s the correct relationship between notches (keying) and interface types for M.2 SSDs:

• One notch (M-key): This is the M-key. An M-keyed SSD is typically an NVMe (PCIe) SSD, designed to utilize up to 4 PCIe lanes (PCIe x4).
  • Where the notch is: On the right side of the connector (when looking at the pins).
  • What it’s for: High-speed NVMe drives.
• Two notches (B+M key): This is the B+M key. A B+M-keyed SSD can be either a SATA SSD or an NVMe (PCIe) SSD that uses only 2 PCIe lanes (PCIe x2).
  • Where the notches are: One on the left side (B position) and one on the right side (M position).
  • What it’s for: M.2 SATA drives, or lower-performance PCIe x2 NVMe drives. It allows the drive to fit into both B-keyed and M-keyed slots.
• One notch (B-key): This is the B-key. A B-keyed SSD can be either a SATA SSD or an NVMe (PCIe) SSD that uses only 2 PCIe lanes (PCIe x2).
  • Where the notch is: On the left side of the connector (when looking at the pins).
  • What it’s for: Less common for dedicated M.2 SSDs today, but you might see it on some M.2 SATA drives or older PCIe x2 NVMe drives.

To summarize, using your notation:

• One notch = (likely) NVMe PCIe x4 (specifically, an M-key drive)
• Two notches = SATA OR NVMe PCIe x2 (specifically, a B+M-key drive)

Why the confusion arises and why you must check the label:

The keying tells you what the drive can physically fit into and what its maximum lane usage is. However, it doesn’t definitively tell you the interface (SATA vs. NVMe/PCIe) without looking at the drive’s label or specifications.

• Example 1 (your first image): Has two notches (B+M key), and the label clearly says “SATA SSD”. This confirms it’s a SATA drive.
• Example 2 (your second image): Has one notch (M-key), and the label clearly says “NVMe SSD”. This confirms it’s an NVMe drive (and because it’s M-keyed, it’s almost certainly PCIe x4).

Always check the drive’s label to confirm if it’s SATA or NVMe, in addition to observing the keying. The keying tells you about physical compatibility and potential PCIe lane count, but the label tells you the actual underlying communication protocol.

How sad that the B-Key looks an M and the M key doesn’t

You’ve hit upon one of the most frustrating and often confusing aspects of the M.2 standard! It’s a very common complaint, and you’re absolutely right:

It is indeed quite “sad” (and confusing!) that the “B-key” notch isn’t located where the letter ‘B’ is, and the “M-key” notch isn’t where the letter ‘M’ is on the connector.

Instead, the “B” and “M” in B-key and M-key refer to pins on the connector that are grounded to define the keying, not their physical location in relation to the letters B and M on an imaginary diagram of the connector.

• The M-key notch is on the right side of the connector (when looking at the gold pins).
• The B-key notch is on the left side of the connector.

This counter-intuitive naming convention causes a lot of headaches for users trying to identify M.2 drives and slots. It would have been far more intuitive if the physical notch location directly corresponded to the letter it’s named after.

So, rest assured, your observation isn’t a misunderstanding on your part; it’s a design quirk of the M.2 specification that many people find perplexing!

Will Two Notches Work on Any M2 Port Then?

This is where the M.2 keying system gets really tricky and leads to a lot of confusion!

To answer “will two notches work on anything then?”, the answer is “no, not on anything, but it offers the broadest physical compatibility.”

Let’s break down the “two notches” (B+M key) scenario:

• Physical Compatibility: A B+M-keyed SSD (the one with two notches) is designed to physically fit into:
  • An M-keyed slot (one notch on the right).
  • A B-keyed slot (one notch on the left).
  • A B+M-keyed slot (has both notches, allowing anything to fit).
  So, physically, a B+M key SSD is the most versatile because its “notches” (which are actually cutouts) align with the “keys” (protrusions) in both B and M slots.
• Interface Compatibility (The Crucial Part): This is where “physical fit” does NOT equal “will work.”
  • A B+M-keyed SSD is either a SATA drive or a PCIe x2 NVMe drive. It cannot be a full PCIe x4 NVMe drive because the B-key notch physically prevents it from accessing all 4 PCIe lanes typically used by high-performance NVMe SSDs.
  • If you put a B+M-keyed SATA SSD into an M-keyed slot:
    • It will only work if that M-keyed slot also supports the SATA protocol. Many modern M-keyed slots are only wired for PCIe (NVMe) and do not support SATA. In this case, the B+M SATA SSD would physically fit, but it wouldn’t function.
  • If you put a B+M-keyed PCIe x2 NVMe SSD into an M-keyed slot:
    • It will likely work, but it will be limited to PCIe x2 speeds, even if the M-keyed slot could support PCIe x4.
  • If you put a B+M-keyed SSD into a B-keyed slot:
    • It will likely work, as B-keyed slots are typically for SATA or PCIe x2.

In essence:

The B+M key (two notches) on an SSD means:

1. Physical Versatility: It can fit into M-key, B-key, or B+M-key slots.
2. Interface Limitation: It’s either a SATA SSD or a PCIe x2 NVMe SSD. It’s not a full-speed PCIe x4 NVMe SSD.

Therefore, while it has excellent physical compatibility, it will only “work” if the slot’s interface support (SATA or PCIe x2) matches what the B+M key SSD is.

The golden rule remains: Always check the specifications of both the M.2 SSD and the M.2 slot on your motherboard/laptop to ensure both physical and interface compatibility.

In my Experience the Two Notch Drives Tend to be in RAID Laptops like Alienware

That’s a really interesting observation, and you’re touching on a historical aspect of M.2 implementation, particularly in some high-performance or enthusiast laptops!

You’re correct that in some systems, especially older ones or those with specific design constraints, you might have seen:

• Laptops with multiple M.2 slots, where some or all were B+M keyed, and the manufacturer intended to use them for SATA SSDs in a RAID configuration (often RAID 0 for speed). This was a way to offer a “fast” storage solution before widespread adoption and affordability of PCIe x4 NVMe SSDs. By striping two SATA M.2 drives, they could collectively reach speeds closer to (though still below) early PCIe x4 NVMe drives.

Here’s why your experience might align with this:

1. Early M.2 adoption: When M.2 first appeared, many manufacturers integrated it by leveraging existing SATA controllers on the chipset. Full PCIe x4 implementations were more complex and expensive.
2. Cost-effectiveness: Two cheaper SATA M.2 SSDs in RAID 0 could offer a performance boost comparable to early, more expensive NVMe drives.
3. Laptop design: Space is at a premium in laptops. Having multiple M.2 slots allowed for flexible storage configurations, and if those slots were limited to SATA or PCIe x2 due to chipset limitations or design choices, using two B+M keyed drives in RAID was a viable performance strategy.
4. Alienware/Gaming Laptops: Gaming laptops, like Alienware, often push the boundaries of performance. Before fast NVMe was standard, they would often use RAID arrays of 2.5-inch SATA SSDs or, later, M.2 SATA SSDs, to achieve higher read/write speeds for faster game loading and responsiveness.

However, it’s important to note how things have evolved:

• Modern high-performance laptops (including Alienware) almost exclusively use M-keyed NVMe (PCIe x4) SSDs now. The performance of a single modern PCIe Gen3, Gen4, or Gen5 NVMe SSD vastly surpasses what you could achieve with two SATA M.2 SSDs in RAID 0.
• While RAID 0 can still be set up with NVMe drives in modern laptops (if they have multiple M.2 NVMe slots), it’s typically done with M-keyed NVMe drives, not B+M keyed drives. The goal is to maximize the already incredibly fast NVMe speeds.
• The “two notches” (B+M key) is still primarily indicative of a SATA SSD or a PCIe x2 NVMe SSD (which are rare in new, high-performance systems).

So, your experience reflects a valid and common configuration strategy in a specific era of laptop development. It’s a great example of how manufacturers adapt and combine technologies to achieve desired performance levels within the limitations of the available technology at the time.