SN850X vs 990 Pro: Which NVMe SSD Wins?

The WD Black SN850X and Samsung 990 Pro are both flagship PCIe 4.0 NVMe SSDs, and for most users the 990 Pro is the better all-round choice thanks to slightly higher random read/write speeds and a more efficient controller, while the SN850X offers a cheaper per-gigabyte price and a larger 8TB capacity option. Both drives deliver real-world performance that is nearly indistinguishable in everyday tasks, so your decision comes down to price, capacity, and a few specific features.

Background: The Flagship NVMe Battle

Both the WD Black SN850X and Samsung 990 Pro are PCIe 4.0 x4 NVMe drives released in 2022. They were designed to push the limits of the PCIe 4.0 interface, with sequential read speeds up to 7,450 MB/s for the SN850X and 7,450 MB/s for the 990 Pro (the 990 Pro’s 1TB and 2TB models hit 7,450 MB/s; the 4TB version reaches 7,450 MB/s as well). These numbers are essentially the ceiling for PCIe 4.0, so the difference is negligible in real-world use.

Both drives use 3D TLC NAND flash and have a similar endurance rating: 600 TBW for the 1TB model, 1,200 TBW for the 2TB, and 2,400 TBW for the 4TB. The SN850X adds a 8TB option (with 4,800 TBW) that Samsung doesn’t offer.

Performance: Real-World Differences

In synthetic benchmarks, the 990 Pro often edges out the SN850X in random read/write IOPS. For example, the 990 Pro’s 2TB model has a random read speed of 1,400K IOPS and random write of 1,550K IOPS, while the SN850X 2TB is rated at 1,300K IOPS read and 1,400K IOPS write. In day-to-day tasks like booting Windows, loading games, or transferring large files, you won’t notice the difference—both are faster than the PCIe 3.0 SSDs they replace.

One area where they differ is sustained write performance. The 990 Pro maintains high write speeds even after the cache fills, while the SN850X can slow down more noticeably during long writes. For video editing or other sustained write workloads, the 990 Pro has a slight edge.

Features and Software

Both drives come with proprietary software: WD’s Dashboard and Samsung’s Magician. Both allow firmware updates, health monitoring, and performance optimization. The 990 Pro supports a “Power Loss Protection” feature (using capacitors to flush the cache during sudden power loss), while the SN850X does not. The SN850X has a “Game Mode” that can be enabled in the Dashboard, but its real-world benefit is minimal.

Both drives come in versions with and without a heatsink. The SN850X heatsink version is slightly thicker, so check your motherboard or laptop clearance. The 990 Pro’s heatsink is slimmer and more compatible with laptops and PS5 consoles.

How to Choose: Which One Should You Buy?

Consider the following factors when deciding:

• Price per GB: The SN850X is often cheaper per terabyte, especially during sales. If budget is your priority, it’s the better value.
• Capacity: If you need 8TB, the SN850X is your only option. The 990 Pro tops out at 4TB.
• Random performance: If you run heavy database workloads or many small file operations, the 990 Pro’s higher IOPS may be worth the extra cost.
• Power efficiency: The 990 Pro is more power-efficient, which can benefit laptop battery life and thermals.
• Compatibility: Both work in PS5 and most motherboards with PCIe 4.0 slots, but check the heatsink clearance.

Common Problems and Misconceptions

A common misconception is that the SN850X’s higher sequential read speed (7,300 MB/s vs 7,450 MB/s) means it’s faster. In reality, sequential speeds are rarely the bottleneck in real-world use. Another issue is that both drives can run hot under sustained load. The 990 Pro has a more efficient controller, but both benefit from a heatsink, especially in a PS5 or a laptop.

Some users report that the SN850X’s firmware updates can occasionally cause performance drops, but these are usually fixed quickly. The 990 Pro had an early firmware bug that caused rapid health degradation, but it was resolved with a firmware update. Always update your firmware after installation.

Cost and Value

Prices fluctuate, but generally the SN850X is 5-10% cheaper per TB than the 990 Pro. For a 2TB drive, that could mean a $20-30 difference. If you’re building a high-end gaming PC and want the best performance per dollar, the SN850X is the smarter buy. If you need the absolute best random performance and power efficiency, the 990 Pro justifies its premium.

Alternatives

If you don’t need the absolute top speed, consider the WD Black SN770 or Samsung 980 Pro (the previous generation). They are cheaper and still offer excellent performance. If you want PCIe 5.0 speeds, the Corsair MP700 or Crucial T700 are options, but they require a PCIe 5.0 motherboard and run hotter. For budget builds, the Crucial P3 Plus or WD Blue SN580 are solid choices.

Frequently Asked Questions

Which SSD is faster in gaming?

In gaming, both are effectively identical. Load times are limited by the game engine and CPU, not the SSD. You won’t notice a difference between the SN850X and 990 Pro in any current game.

Can I use these SSDs in a PS5?

Yes, both are compatible with the PS5. The PS5 requires a PCIe 4.0 NVMe SSD with a heatsink. Both the SN850X and 990 Pro have heatsink versions designed for the PS5.

Do I need a heatsink for these SSDs?

It’s recommended. Both drives can throttle under sustained load without adequate cooling. Most motherboards come with a heatsink for M.2 slots, but if yours doesn’t, buy one.

How long will these SSDs last?

With a 600 TBW rating for the 1TB model, you’d need to write 600 TB of data before the warranty expires. For a typical user writing 20 GB per day, that’s over 80 years. They’ll last longer than your computer.

Is the 990 Pro worth the extra money?

If you value the slightly higher random performance, better power efficiency, and power loss protection, yes. If you’re on a budget, the SN850X is a better value and you won’t notice the difference in most tasks.

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