I had high hopes for the company’s newest PCIe 5.0 WD Black SN8100 because WD’s 8TB Black SN850X was our best-rated PCIe 4.0 SSD, and the WD Black SN7100 was the second-ranked HMB (host memory buffer) PCIe 4.0 SSD. For reasons that are still unknown, I received both fantastic and not-so-great items.

Please take note that if and when the “things” problem with the SN8100 (see the performance part) improves, I will go over this review again. Additionally, Sandisk appears to be marketing WD drives following a recent “split” from WD; this is the Sandisk WD Black SN8100.

Features

The WD Black SN8100 is a 2280 (22 mm wide, 80 mm long) M.2 SSD with PCIe 5.0 and NVMe 2.0. For quick random operations, it makes use of stacked BiCS8 TLC NAND, a Sandisk controller, and DRAM.

Due to the WD Black SN8100’s 600 TBW per terabyte of capacity rating, Sandisk offers a five-year warranty. If you write more than 600TB to the drive, it may enter read-only mode, at which time the warranty is nullified. It’s improbable that you will write nearly as much in even ten years, since the majority of SSDs are capable of significantly more writes than their rating.

Cost

Three capacities are available for the WD Black SN8100 from Sandisk: 1TB costs $180, 2TB (tested) costs $280, and 4TB costs $550. Although it is almost identical to their MSRPs, it is more than the Samsung 9100 Pro and the similarly quick Crucial T705, which are now on sale for $170 and $142, respectively. The SN8100 should settle in at a competitive price, in my opinion. That would make it a decent value if everything else were equal, but

Performence

The SN8100 was on par with its fastest PCIe 5.0 rivals when it was functioning properly. But I had a somewhat similar problem with the WD Black SN8100, right after the Sandisk Extreme Pro SSD with USB4 (that’s the real name) didn’t always connect at full speed. Only with writes, though. The 8100 originally functioned as expected while using the same M.2/PCIe 5.0 slot that I have used to successfully test every NVMe SSD over the past two years. However, write rates in synthetic benchmarks subsequently unexpectedly decreased to 2 GBps/PCIe 3.0 levels, 600 MBps/SATA levels, and even lower levels.

Additionally, the phenomenon was quite erratic: performance would be as expected one day and then completely collapse the next. The problem would emerge and then reappear after reboots. The WD Black SN8100 was moved to a ROG PCIe 5.0/NVMe adaptor card that was tucked away in the test bed’s only PCIe 5.0 slot. Write performance continuously met expectations, constantly tracking at 13.5 GBps throughout all simulated testing.

Since the SN8100 never broke 50 degrees Celsius, thermals were not a problem. But because Sandisk boasts about the drive’s exceptional energy efficiency, perhaps there’s another explanation for its slowing of writing, which uses a lot more energy than reading. The numbers on the charts are from the initial tests in the standard M.2 slot because I retested the two competing drives—Samsung’s blistering 9100 Pro and Crucial’s insane T705—on the adaptor card, although both drove significantly worse. They don’t need to be punished for WD/Sandisk’s problem. Despite those limitations, the SN8100 performed admirably, even winning a few tests.

Conclusion

Based on synthetic benchmarks, the WD Black SN8100 is among the fastest NVMe SSDs I’ve ever evaluated. But trust me when I say that it pains me to suggest that you use CrystalDiskMark 8 or something similar to verify compatibility before making a purchase—WD/Sandisk has, until lately, only produced excellent storage products. Once more, I’ll go over this review again if anything changes, ideally with a better star rating and a resolution to the enigma of the unequal write performance.