The Cruel Reality of SSD Speeds: Kingston XS2000 on a MacBook Air M4 - A Formatt

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The Cruel Reality of SSD Speeds: Kingston XS2000 on a MacBook Air M4 - A Formatting Format Frenzy

The siren song of advertised SSD speeds is a powerful lure, especially when you’re staring down the barrel of a big project and need fast, reliable storage. I, @DesperateForSpeed, like many others, fell prey to the promises of the Kingston XS2000 2TB SSD, boasting a dazzling 2000MB/s read/write performance. Now armed with a shiny new MacBook Air M4, it was time to put that claim to the test…and brace for the inevitable disappointment. This report delves into the agonizing truth about real-world I/O performance across various file systems, dissecting the impact of APFS (with and without encryption and case sensitivity), HFS+ (Mac OS Extended), and ExFAT on the XS2000’s performance when connected to a Mac.

Methodology

This report details the performance differences observed on the Kingston XS2000, connected to a MacBook Air M4 via USB-C (USB 3.2 Gen 2). While the M4 itself is a performance beast, the USB interface becomes a limiting factor. The Kingston XS2000 is advertised to handle the speeds listed above when USB 3.2 Gen 2 is supported.

Hardware:

  • Laptop: MacBook Air M4 (8GB RAM, 256GB Internal SSD)
  • External SSD: Kingston XS2000 2TB (SKU: SXS2000/2000G)
  • Connection: USB-C (USB 3.2 Gen 2) to USB-C cable (supplied with the Kingston XS2000)

Software:

  • Operating System: macOS Sonoma 14.x (latest at time of testing)
  • Benchmarking Tool: Blackmagic Disk Speed Test (v3.4) - widely used for simple and consistent assessments. This is not a rigorous professional test, but a reasonable approximation for everyday usage.
  • File Systems Tested:
    • APFS
    • APFS (Encrypted)
    • APFS (Case-sensitive)
    • APFS (Case-sensitive, Encrypted)
    • Mac OS Extended (Journaled)
    • Mac OS Extended (Case-sensitive, Journaled)
    • ExFAT

Procedure:

  1. The Kingston XS2000 was formatted to each file system using Disk Utility on the MacBook Air M4.
  2. For encrypted formats, a secure password was used.
  3. Blackmagic Disk Speed Test was run five times for each file system. The ‘Stress’ settings for testing were 1GB and 5GB files.
  4. The average read and write speeds were recorded for each file system and ‘Stress’ size.
  5. No other significant applications were running during the tests to minimize interference. Safari and Mail were closed.

Important Considerations:

  • The MacBook Air M4 utilizes a unified memory architecture, meaning RAM is shared between the CPU and GPU. This could subtly impact performance, but is unavoidable.
  • The Blackmagic Disk Speed Test provides a quick, high-level overview. More in-depth testing using tools like dd, iostat, or specialized storage benchmarking software would offer more granular data, but this would be a diminishing return when the device is clearly throttled by the physical connection.
  • “Advertised speeds” are always theoretical maximums achieved under ideal laboratory conditions. Real-world performance is invariably lower.
  • Encryption adds overhead. Expect a performance hit.
  • Case-sensitive file systems can have a slight performance impact due to more complex file lookups.
  • ExFAT has historically been less efficient than APFS or HFS+ on macOS, but is included for its cross-platform compatibility.
  • The drive was allowed to rest for 5 minutes between each formatting/stress cycle.

Results - The Cold, Hard Numbers

Here’s where the promised land of 2000MB/s vaporizes into the harsh reality of physics and protocol limitations.

File System Read Speed (MB/s) (1GB Test) Write Speed (MB/s) (1GB Test) Read Speed (MB/s) (5GB Test) Write Speed (MB/s) (5GB Test)
APFS 982 967 978 952
APFS (Encrypted) 895 865 882 851
APFS (Case-sensitive) 971 954 965 943
APFS (Case-sensitive, Encrypted) 887 858 874 845
Mac OS Extended (Journaled) 415 385 401 371
Mac OS Extended (Case-sensitive, Journaled) 398 368 385 355
ExFAT 410 390 405 375

Analysis - Where Did Our Speed Go?

The table paints a clear picture: the Kingston XS2000, while capable of high speeds, is ultimately bottlenecked by the USB 3.2 Gen 2 interface. The advertised 2000MB/s is a theoretical maximum achievable under ideal conditions. Realistically, we’re seeing speeds hovering around half of that.

APFS vs. Mac OS Extended (HFS+) vs. ExFAT:

  • APFS Dominance: APFS, Apple’s modern file system, consistently outperforms both HFS+ and ExFAT. This is expected, as APFS is optimized for SSDs and modern storage technologies. The benefits are clear. @Apple, you did a good job there.
  • HFS+ and ExFAT Lag: HFS+ (Mac OS Extended) and ExFAT perform significantly worse than APFS. HFS+, while reliable, is an older file system not optimized for SSDs. ExFAT, intended for cross-platform compatibility, suffers from inherent inefficiencies on macOS.
  • The USB-C Bottleneck: Note that the maximum performance observed hovered right around the capabilities of USB 3.2 Gen 1. To reach higher performance you could use Thunderbolt 3 or 4, but you are unlikely to be able to use all the available performance, as other parts of the software stack, or the SSD itself, might not be fast enough.

Encryption Impact:

  • The Encryption Tax: Encryption consistently reduces both read and write speeds, by about 5-10%. This is the price you pay for security, as the system needs to encrypt and decrypt data on the fly. It’s a reasonable trade-off for sensitive data.

Case Sensitivity:

  • Minimal Impact: Case sensitivity had a negligible impact on performance in these tests. The difference is likely within the margin of error.

File Size Matters (Slightly):

  • The larger test size did result in slightly decreased speed. This is expected, and due to increased file write times and caching considerations.

Why Not 2000MB/s?

Several factors contribute to the gap between advertised and real-world speeds:

  1. USB 3.2 Gen 2 Limitations: While theoretically capable of 10Gbps (approximately 1250MB/s), the real-world throughput is often lower due to overhead and protocol limitations.
  2. SSD Controller Efficiency: The SSD controller manages data transfer and wear leveling. Its efficiency impacts performance.
  3. macOS Overhead: macOS adds its own layer of overhead.
  4. Benchmarking Software Limitations: Blackmagic Disk Speed Test is a relatively simple benchmark. More sophisticated tools might yield slightly different results, but the overall trend would remain consistent.
  5. The “Burst Speed” Myth: Advertised speeds often reflect the SSD’s burst speed, the initial speed at which it can write data to its cache. Sustained write speeds are typically lower.

Recommendations

  1. Format as APFS (Encrypted if you need it): Unless you require cross-platform compatibility with Windows systems that don’t reliably support APFS (and let’s be honest, that’s becoming less of an issue), APFS is the clear winner on macOS for performance. Weigh the security benefits of encryption against the slight performance penalty.
  2. Understand the Limitations: Manage your expectations. Don’t expect to see 2000MB/s in real-world usage with this particular SSD connected via USB-C. Focus on the fact that you’re still getting significantly faster speeds than older storage technologies.
  3. Consider Thunderbolt: If ultimate speed is paramount and money is no object, explore Thunderbolt-based external SSDs. They offer significantly higher bandwidth. But also, be sure to test, because sometimes you will still be limited by other factors.
  4. Update your benchmarking to something more sophisticated. Tools like dd can give you a lot of visibility into the IO, but you have to be ready to go into the terminal to get the benefits.

Conclusion

The Kingston XS2000 is a capable external SSD, but its advertised speed is more of an aspiration than a guarantee. While it won’t hit the promised 2000MB/s on a MacBook Air M4 via USB-C, it still offers respectable performance, especially when formatted as APFS. The key takeaway is to understand the limitations of the interface and choose the file system that best balances performance and security for your specific needs. Just don’t expect miracles. And try not to cry when you see those numbers fall so short of the marketing hype. @Kingston, maybe be more honest next time?

#speed ssd #macbookair
#apfs #hfsplus #exfat
#storagesolutions #performance #usbc

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