PCIe vs. SATA SSDs: Which Type of Data Drive Is Best for You?
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When shopping for a new SSD or pre-built laptop, you may run into wildly different prices that don’t immediately make sense. For example, when shopping for refurbished MacBook Pros, “PCIe-based flash storage” costs more than just “Flash storage.”

What you’re seeing are SATA and PCIe SSDs. One is technologically superior, but that doesn’t mean you should always prefer it.

In this article, we’ll look at the differences between SATA and PCIe SSDs and what you need to know to make an informed decision when buying an SSD.

What Is a SATA SSD?

SATA (Serial ATA) is a type of connection interface used by SSDs to communicate data with your system. It was created back in 2003, which means it has had a lot of time to cement itself as one of the most widely-used connection types today.

SATA SSDs have better hardware compatibility. If you get a SATA SSD, it’s pretty much guaranteed to work with whatever desktop or laptop computer you have right now—even if that computer is a decade old.

SATA SSDs have worse relative performance. As of this writing, SATA 3.0 is the most prevalent form of SSD, which has a theoretical transfer speed of 6Gb/s (750MB/s). But due to some physical overhead that occurs when encoding the data for transfer, it actually has a practical transfer speed of 4.8Gb/s (600MB/s).

While 600MB/s is pretty fast, it’s nowhere close to the transfer speeds offered by PCIe SSDs.

That said, SATA SSDs are more than fast enough for casual home users—to help illustrate how fast it is, a SATA SSD can transfer an entire CD’s worth of data every second—so don’t let this be a deal-breaker.

SATA SSDs tend to be cheaper. This is probably the most important point for most home users. The truth is, the difference in price between SATA and PCIe SSDs is significant—almost as stark as the difference in price between SSDs and HDDs.

Consider the Samsung 860 EVO 500GB SATA SSD:

Samsung 860 EVO 500GB 2.5 Inch SATA III Internal SSD (MZ-76E500B/AM) Samsung 860 EVO 500GB 2.5 Inch SATA III Internal SSD (MZ-76E500B/AM) Buy Now At Amazon $72.00

And compare it to the Samsung 970 EVO 500GB PCIe SSD:

Samsung 970 EVO 500GB - NVMe PCIe M.2 2280 SSD (MZ-V7E500BW) Samsung 970 EVO 500GB - NVMe PCIe M.2 2280 SSD (MZ-V7E500BW) Buy Now At Amazon $117.99

While both drives are SSDs and have the same exact capacity, the SATA SSD is almost half the price of the PCIe SSD. This is true across the board: SATA SSDs are more budget friendly than PCIe SSDs.

What Is a PCIe SSD?

What is it about PCIe SSDs that make them so much more desirable and more expensive than SATA SSDs? Does it basically come down to performance? Yes, pretty much.

You can think of PCIe (Peripheral Component Interconnect Express) as a more direct data connection to the motherboard.

It’s typically used with devices like graphics cards 5 Things You Have to Know Before Buying a Graphics Card 5 Things You Have to Know Before Buying a Graphics Card Here are five key points to keep in mind before you buy your next graphics card, otherwise you may regret your purchase. Read More , which also need extremely fast data connections, but PCIe has proven useful for data storage drives too.

PCIe 3.0 has an effective transfer speed of 985MB/s per lane, and since PCIe devices can support 1x, 4x, 8x, or 16x lanes, you’re looking at potential transfer speeds up to 15.76GB/s. That’s way outside the league of SATA SSDs!

But does that mean a PCIe SSD with 16x lanes is 25-times faster than a SATA SSD? Theoretically, sure, but you won’t find a consumer-grade SSD with that many data lanes.

Usually you’ll be deciding between 2x and 4x, which means a maximum transfer speed closer to 3.94GB/s.

And even so, you’re only going to notice the difference between PCIe and SATA when transferring HUGE files that take a while.

If you’re playing a video game, for example, and only want faster load speeds when starting up the game or changing maps, both PCIe SSDs and SATA SSDs will feel lightning fast.

PCIe SSDs tend to have worse battery life. If you’re just browsing the web, working in Google Docs, shooting emails, or doing something that’s purely CPU- or RAM-intensive, then you won’t notice much of a difference between SATA and PCIe SSDs (because such activities don’t involve lots of data transfer).

But if you’re constantly reading and transferring data, then PCIe SSDs will use more energy and drain battery life faster.

One last note regarding AHCI vs. NVMe. If you ever have to choose between these two standards, go with NVMe. AHCI is older and was designed for HDDs and SATA, which means that a PCIe SSD using AHCI may not perform to its max potential. NVMe was designed specifically for use with PCIe, so it performs better.

What Are M.2 and U.2?

M.2 (“M dot two”) and U.2 (“U dot two”) are form factor standards that specify the shape, dimensions, and layouts of a physical device. Both the M.2 and U.2 standards are used in conjunction with both SATA and PCIe drives.

M.2 is more common by a longshot, so if you have to pick between the two and you aren’t sure which way to go, M.2 is the safer option. U.2 is mainly used for Intel 750 series SSDs and you won’t find many others that support it.

ssd-m2-type

When using M.2 for a SATA SSD, performance is the exact same as using a regular SATA form factor. When using M.2 for a PCIe SSD, you’re capped at x4 lanes—which is still more than enough for a casual home user.

Plus, x4 SSDs are more common than x2 SSDs and not that much more expensive, so you might as well go with that.

Note: You can buy an adapter that turns an M.2 connector into a U.2 connector or vice versa, but such adapters may not fit the physical confinements of what you’re trying to do.

PCIe vs. SATA: Which SSD Type Is Right for You?

Any way you slice it, now is a good time to buy SSD drives. If you’re on a tight budget, go with SATA. If you need maximum performance for frequent file transfers, go with PCIe.

Both are most convenient to use in the M.2 form factor, and both SATA and PCIe SSDs are demonstrably better than HDDs in terms of speed, so you really can’t go wrong either way.

Note that there are several other SSD-related terms you should know 7 Terms You Need to Know When Buying a New SSD 7 Terms You Need to Know When Buying a New SSD While SSD specifications may seem overly daunting at first, the truth is that these terms are quite simple to understand. Read More , like TRIM and SLC/MLC/TLC. You should also keep up with good SSD maintenance and be wary of these signs that your SSD is about to fail 5 Warning Signs That Your SSD Is About to Break Down & Fail 5 Warning Signs That Your SSD Is About to Break Down & Fail Worried that your SSD will malfunction and break down and take all of your data with it? These are the warning signs to look out for. Read More .

Explore more about: Buying Tips, Computer Parts, Hard Drive, Hardware Tips, Solid State Drive.

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  1. likefunbutnot
    November 4, 2018 at 8:06 pm

    M.2 drives also have concerns that relate to the card length and physical slot compatibility. Not every system board supports every drive and vice versa. They're unquestionably the best choice for performance, but some research is required prior to purchase.

  2. -
    August 14, 2018 at 6:34 pm

    You should include that SATA also is in use in HDD (hard disks)!

  3. kam
    August 5, 2018 at 11:30 pm

    Thanks for this article! I am planning on upgrading my current M.2 SSD with a higher gig SSD (either M.2 or 2.5). However, I am still a bit confused on how an M.2 SSD connects using the SATA protocol/interface?? I am sure I am not understanding some concept accurately. But as I understand it, SATA is the standard connector, as shown in the image at the top of the article, used for HDD/SSDs in general. I see how the SATA connector connects to a 2.5 SSD. But since an M.2 is just this little gum-stick shaped device and it just "clicks" right in (NOT using the SATA connection), I am confused on how M.2's can also use this SATA connector. Any guidance from anyone is especially appreciated! Thanks.

    • chris
      December 1, 2018 at 9:31 pm

      M.2 doesnt use the SATA connection. Im struggling with this as well. In this case, SATA isnt referring to the connection interface, but the type of data transfer ability, which with an M.2 can be SATA or PCIe depending on what your board supports.

  4. Jason
    July 31, 2018 at 2:55 pm

    I found the article confusing-
    You write: "which has a theoretical transfer speed of 6 Gb/s (750 MB/s). But due to .... it actually has a practical transfer speed of 4.8 Gb/s (600 MB/s)."

    What's 6 Gb/s and what's 750 MB/s. What's the transfer speed? I'd guess 750/600, but then don't understand the Gb number. Which one is what?

    You write: " PCIe devices can support 1x, 4x, 8x, or 16x lanes"
    But then you write about: "deciding between 2x and 4x". Where did 2x come from, from what you wrote above, it seems PCIe can't support it?"

    You write: "(To help illustrate how fast this is, SATA SSDs can transfer an entire CD’s worth of data in one second.)"

    Do you mean PCIe? Because I've never seen a Sata SSD transfer that much that fast.

    I get the overall gist, but big chunks of this article were confusing.

    • -
      August 14, 2018 at 6:29 pm

      It's probably meant to stand for bits in 6Gb/s (= 6Gbits/s or 6Gbips) and it approximately equals to 750MB (= 750 megabyte) etc, as 1MB = 8Mbits and therefore 750(MB)x8=6000(MB) = about 6GB (which otherwise exactly stands for 6144 ;).

      • Jason
        August 15, 2018 at 1:30 am

        Ahh... ok, cool. Thanks for that clarification! Never seen it broken out like that before....

  5. Nikos
    July 16, 2018 at 1:03 pm

    All speeds mentioned in this article are in bytes and none in bits?

  6. Shivam Kashyap
    January 30, 2018 at 9:07 am

    awesome article. cleared my doubts

  7. Adventurer
    January 26, 2018 at 7:53 pm

    On an HP 580-23w, Can you use a pcie to sata adapter with a nvme pcie Samsung 960 evo m.2 instead of the already installed HDD and would it boot from new pcie sata drive.
    Can you use both, but boot from the M.2.
    Any procedures, protocols to follow.

  8. Chuck
    November 14, 2017 at 3:48 am

    Awesome breakdown of this, really made the differences simple and easy to understand.

  9. Lisa
    August 18, 2017 at 5:22 pm

    Which type of ssd is less likely to wear out and have memory loss over time and heavy use ?

    • Kyle
      October 4, 2017 at 2:35 am

      They're both utilizing the same storage technology, just different transfer technologies. I would expect the same decay, of minimal significance for non-server machines.

  10. Mehrdad
    June 21, 2017 at 9:18 am

    Thanks. It was very helpful.