56 PCWorld JANUARY 2021REVIEWS WD BLACK SN850 NVME SSD
WD’s Black SN850 was darn close (but no cigar) to
the Samsung 980 Pro in real-world transfer tests.Total Time
239
32225148GB transfers
Seconds
WD Black SN850 PCIe 4 Samsung 980 Pro PCIe 4
Seagate FireCuda 520 PCIe 4 WD Black SN850 PCIe 3321
48GB Folder Write
98
12899129SHORTER BARS INDICATE BETTER PERFORMANCE48GB Folder Read
97
153108139
48GB Write48GB Read2522
2222
22222819the CrystalDiskMark 6 sequential write test by
a small margin, for instance, but it trailed by
nearly 1GBps in the CDM sequential read
test—a substantial margin. However, the
random 4K performance of the drives is nearly
identical. That last test is largely what
determines how sprightly the drive feels
when running an operating system.
The 48GB transfer tests told pretty much
the same story as CrystalDiskMark 6. TheSN850 is very competitive with the Samsung
980 Pro, but it couldn’t quite pull out the
victory.
Then there was this, in our 450GB single-
file write test. The SN850 was a monster,
shaving a whopping 49 seconds off of the
980 Pro’s time. Only WD’s AN1500 RAID 0,
dual SSD card has posted a faster time (194
seconds). Whatever WD’s doing with long
writes (the extra NAND available in a 2TB
model likely helped), the company should
keep doing it.
Both the SN850 and 980 Pro are super-
fast SSDs that don’t slow down during long
writes, but the WD is special with very large
files. You may not perform such a task very
often, but the WD still chalks up a win.
The PCIe 3 tests utilized Windows 10
64-bit running on a Core i7-5820K/Asus X99
Deluxe system with four 16GB KingstonThe SN850 turned in by far the fastest time
we’ve seen writing our single 450GB file. It was
45 seconds faster than the next fastest drive
(Sabrent’s Rocket Q 8TB), and 49 seconds faster
than the 980 Pro.450GB Write
258
290209450GB Single-File Write
Seconds
WD Black SN850 PCIe 4 Samsung 980 Pro PCIe 4
Seagate FireCuda 520 PCIe 4 WD Black SN850 PCIe 3242
SHORTER BARS INDICATE BETTER PERFORMANCE