Conclusion

The WD Blue SN500 defies expectations. Its basic specifications say it's an entry-level NVMe drive: only two PCIe lanes (so it can't possibly exceed 2GB/s), a DRAMless controller that isn't using the NVMe Host Memory Buffer feature either, and a tiny SLC write cache. And our review sample is a 250GB model, which is the smallest drive capacity that can come close to offering decent performance when using just a handful of modern high-capacity NAND flash dies.

What we are accustomed to seeing from low-end NVMe drives is peak performance that's impressively high compared to SATA, but with caveats in the form of severely reduced performance in suboptimal conditions. What makes or breaks a low-end DRAMless SSD (even on NVMe) is usually not the question of how abysmal its worst case performance is, but whether that worst-case performance can be avoided during real-world usage.

The WD Blue SN500 doesn't buckle under the pressure of our most intense tests, and it performs surprisingly well on The Destroyer even when compared against some high-end NVMe models of similar capacity. The SN500's SLC cache is tiny, but the performance after the cache is full is pretty good for a 250GB drive, and it's not noticeably interrupted or degraded by garbage collection cycles. Compared to the other small entry-level NVMe SSDs we've tested, the SN500 is a clear winner. It doesn't come out ahead in every single test, but the overall performance profile is much more consistent. The SN500 at its worst is still a decent SSD.

The WD Blue SN500 is not a high-end NVMe drive and it is not at all hard to find cases where the typical high-end NVMe drive with a PCIe x4 connection is much faster than the SN500. But on the tests with more realistic IO patterns, the gap between the SN500 and the top tier of drives isn't huge.

Western Digital was late to the game with in-house NVMe SSD controllers, but they clearly took the time to get it right. Both the high-end WD Black and mainstream WD Blue SSD product lines (and their OEM counterparts) are now using controllers based on their own controller architecture, and both instantiations of that architecture seem to be very successful for a first-generation release. The two products offer very different performance, but most of the time they have very similar power efficiency that puts them at or near the top of the charts. For the slower WD Blue SN500, that excellent efficiency usually means it's drawing less than 2W under load, though it can occasionally be pushed all the way up to 2.5W. The OEM drive that the SN500 is derived from was intended to fit into the thinnest and lightest notebooks and tablets, and it looks like Western Digital achieved that goal without making any horrible sacrifices (except to maximum drive capacity).

We didn't have a 250GB sample of the older SATA-based WD Blue SSD on hand to compare against, but the 250GB SN500 had no trouble matching or exceeding the performance of the 1TB WD Blue SATA SSD. Since performance generally scales with capacity, this is an illustration both of how good the SN500 is and how ready the mainstream SSD market segment is to break free of the limitations of a SATA interface.

At current pricing, the WD Blue SN500 isn't quite ready to push SATA SSDs out of the market, but it does make it very easy to step up to NVMe without regrets or worries. However, as usual there are some even faster drives for sale in basically the same price range, including the HP EX920 (Silicon Motion SM2262) and the Team MP34 (Phison E12 controller) that we will be reviewing soon. If Western Digital can push the price of their entry-level NVMe drive all the way down to SATA prices, they'll have a very successful product on their hands.

Power Management
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  • jabber - Friday, April 19, 2019 - link

    It will do fine for a Steam drive. Reply
  • fazalmajid - Friday, April 19, 2019 - link

    I don’t see how such puny capacities can be mainstream, specially when most motherboards or laptops have a limited number of M.2 slots. My minimum would be a 1TB or 2TB Intel 660P. Reply
  • kpb321 - Friday, April 19, 2019 - link

    A lot of people don't need much space. I just upgraded my wife from a 128gb SSD to a 256gb SSD. The 128GB SSD was getting a little full because of pictures of our son and I was occasionally having to free up space for Windows update etc. We could have stuck with the 128gb and migrated her entire picture collection to the NAS or kept freeing up space when needed but a 256 SATA SSD is so cheap I figured why not upgrade. Her old 128gb got stuck in my in-law's computer to replace the old slow 500gb hd they had in the system. They are using less than half the space on that SSD so should be fine for a long time and if really needed I can always setup the 500gb hd as a secondary storage drive for them. The old days of 32/64gb SSD being barely adequate are passed. Windows + a decent selection of apps is fine on a 128gb SSD and 256gb gives even more head room. Reply
  • jabber - Saturday, April 20, 2019 - link

    Been running my work laptop on a 64GB SSD for several years now. Some of us don't need to keep masses of data on a device that goes out and about. Sometimes carrying masses of data is a liability. Reply
  • RealBeast - Friday, April 19, 2019 - link

    Don't know about mainstream, but no way that I would waste precious M.2 slots on some small slow drive like this one.

    Sure a .5-2TB, but not really a 660P for me (they should be on SATA ports at my house). I use those ports for fast drives.
    Reply
  • beginner99 - Saturday, April 20, 2019 - link

    In a laptop you might have a point but in a desktop? Put the OS on it and the most used apps like browser. If you don't game you are already set. For games you can use a hdd or a large cheap sata ssd as it doesn't really matter much what you use. Reply
  • stephenbrooks - Sunday, April 21, 2019 - link

    If you have a lot of games you'll want both large capacity and fast access.

    But other than capacity, this "low end" NVMe drive looks great. It's clearly possible for them to do 1TB+ versions in the future too, in one way or another.
    Reply
  • Korguz - Sunday, April 21, 2019 - link

    fazalmajid you may not see it.. but others do.. for me.. i usually use a small drive for my C drive, aka windows drive, before it was 120, now.. as 120 gig drives have next to vanished, im using 250 gig drives, with other bigger drives for other things.. so when it come times for format, and install fresh.. instead of having to move and then redo a big drive.. all i have to deal with, is a small drive with little to no " i want to keep this so i need to move it to another drive " swapping... Reply
  • stephenbrooks - Sunday, April 21, 2019 - link

    I found Windows wants to put "User" data and "Program Files" on the same primary drive, so it can grow in size and even end up containing data I want to keep, even if I try to separate the two. Reply
  • Korguz - Monday, April 22, 2019 - link

    i check those 2 directories as part of the " i want to keep this so i need to move it to another drive " searching, and then moving... :-) Reply

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