WD and Sandisk M.2 SSDs Win Lab Awards for Speed

Verdict: Two Lab Award M.2 SSDs That Earn Their Hype

A PC storage upgrade using a high-end M.2 internal SSD means replacing older SATA or slower PCIe drives with compact “gumstick” modules that plug directly into motherboard or laptop M.2 slots to deliver far higher data throughput and more responsive everyday performance for gaming, content creation, and workstation workloads. Most builders looking for the best internal SSDs will be well served by WD’s Lab Award-winning drives: the PCIe 5.0 WD Black SN8100 and the PCIe 4.0 WD Black SN850X, now also sold under the Sandisk Optimus branding. They are overkill for casual users, but for high-end desktops and gaming laptops that can exploit their speed, they rank as front-runners among more than 100 tested internal SSDs. If your system and budget can support them, these are the performance picks to beat; if not, they’re unnecessary luxury.

How These WD/Sandisk Drives Pulled Ahead in the Lab

The Lab Awards are based on “quantifiable, field-leading technical distinction” in formal testing and real-world relevance to shoppers. PC Labs has benchmarked more than 100 internal SSDs since 2020, then split modern contenders into PCIe 4.0 and PCIe 5.0 M.2 categories to identify performance leaders. According to PC Labs, the WD Black SN8100 (Sandisk Optimus GX Pro 8100) is the PCIe 5.0 speed winner, while the WD Black SN850X (Sandisk Optimus GX Pro 850X) tops the PCIe 4.0 field. Testing uses dedicated storage PCs, secure-erasing drives between runs and applying a set of SSD benchmarks that includes PCMark 10 Full System Drive traces for everyday workloads. In short, these wins aren’t based on vendor claims: they reflect measured M.2 SSD performance against a wide pack of competitors, so builders can trust the ranking when planning a PC storage upgrade.

PCIe 4.0 vs 5.0: Real-World M.2 SSD Performance Trade-offs

On paper, PCIe 5.0 wipes the floor with PCIe 4.0: typical peak sequential reads are around 7,400MBps for PCIe 4.0, versus a little above 14,000MBps for PCIe 5.0. PCIe 5.0 drives are faster as a class and would win any speed competition against earlier generations. But the Lab’s own guidance is pragmatic: if your motherboard only supports PCIe 4.0, the SN850X is already “more than fast enough” for consumer needs. The 4.0-versus-5.0 choice mostly matters on desktops, where newer boards and CPUs can expose PCIe 5.0 bandwidth. Laptops that allow M.2 upgrades largely remain on PCIe 4.0. For gaming and workstation builds, PCIe 5.0 like the SN8100 makes sense when you want maximum SSD benchmarks and have adequate cooling; otherwise, a strong 4.0 drive delivers excellent real-world load times without chasing bleeding-edge specs.

Heat, Efficiency, and the Design of Modern M.2 Drives

Most current internal SSDs use the compact M.2 “gumstick” form factor designed for dedicated motherboard or laptop slots. Traditional 2.5-inch SATA SSDs now appear only rarely in reviews and are tested on standard SATA ports when they do. The big design story for PCIe 4.0 and especially PCIe 5.0 drives is heat and efficiency. Earlier PCIe 5.0 SSDs generated a lot of heat to reach top speeds and often shipped with chunky or even actively cooled heatsinks. Modern controllers and NAND aim to improve energy efficiency, reducing power use and heat output. Testbeds attach any supplied heatsink, or fall back to the motherboard’s integrated M.2 cooling for bare drives. For PC builders, the takeaway is clear: pairing a fast M.2 SSD with sound case airflow and a sensible heatsink is as important as the SSD benchmarks if you want consistent peak performance in a high-end build.

Buy if / Skip if

• Buy the WD Black SN8100 / Sandisk Optimus GX Pro 8100 if you are building a cutting-edge desktop with PCIe 5.0 support and want the fastest tested consumer M.2 SSD performance.
• Skip the WD Black SN8100 / Sandisk Optimus GX Pro 8100 if your motherboard only supports PCIe 4.0 or 3.0, since you will not realize its full speed advantage.
• Buy the WD Black SN850X / Sandisk Optimus GX Pro 850X if you need a best internal SSD for gaming or workstation use on PCIe 4.0 platforms and value proven Lab Award speed over marketing promises.
• Skip the WD Black SN850X / Sandisk Optimus GX Pro 850X if your everyday workloads do not stress storage and a midrange M.2 SSD would feel just as responsive.
• Buy the WD/Sandisk Lab Award drives if you are planning a serious PC storage upgrade for desktops or laptops that depend on M.2 SSDs and you want benchmark-backed choices.
• Skip the WD/Sandisk Lab Award drives if high storage prices or limited budgets make top-end PCIe 4.0 and 5.0 SSDs hard to justify versus more affordable options.