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Head-to-head · Best External SSDs

Corsair EX400U (1 TB) vs Crucial X9 Pro

Which is the better buy? Side-by-side on rating, price, strengths, and watch-outs — with the published ratings we averaged to get there.

The short answer

Corsair EX400U (1 TB) comes out ahead by a clear margin (4.4 vs 4.0). The gap is mostly about fit for purpose — read the strengths below before deciding.

Corsair EX400U (1 TB)
Higher ratedRanked #1 in Best External SSDs
Corsair EX400U (1 TB)
$140

The SSD Review highlighted the Corsair EX400U's exceptional performance, noting it can reach 4GB/s read speeds on Thunderbolt 5 systems, though it cautioned that motherboard implementations often limit USB4 speeds. PCMag's Tony Hoffman praised its unique magnetic Magsafe connector, which allows the drive to securely attach to metal surfaces like the Corsair 6500x case. While the build quality is commended for using Phison controllers and KIOXIA memory, reviewers noted that users must ensure their host device supports USB4 to avoid significant speed bottlenecks. This drive is best suited for users with high-end USB4/Thunderbolt setups who value secure physical attachment, rather than those relying on standard USB 3.2 ports.

Strengths
  • — Achieves up to 4GB/s read and 3.6GB/s write speeds on compatible USB4/Thunderbolt 4 systems
  • — Features a unique magnetic Magsafe connector for secure attachment to metal surfaces
  • — Constructed with high-quality internal components including Phison PS2251-21 controller and KIOXIA TLC memory
Watch-outs
  • — Performance drops significantly to 2GB/s on USB 3.2 ports and 1GB/s on lower-speed connections
  • — Not waterproof despite being shock resistant
  • — Requires specific USB4/Thunderbolt 4 host to achieve advertised maximum speeds
$140 · Buy at alternate.deFull review →
Crucial X9 Pro
Ranked #2 in Best External SSDs
Crucial X9 Pro
$219

StorageReview and The SSD Review highlight the Crucial X9 Pro as an exceptionally compact and lightweight portable SSD, measuring just 65x50mm and weighing 1.34 ounces. While real-world single-threaded tests showed speeds slightly under the advertised 1,050MB/s, multi-threaded workloads closely matched manufacturer claims, making it suitable for creators needing fast transfer rates. Reviewers also praised its rugged build, citing IP55 water/dust resistance and drop-proof durability up to 7.5 feet. However, users must ensure their host device supports USB 3.2 Gen 2 to achieve these peak speeds, otherwise performance will be capped. This drive is best for professionals prioritizing portability and durability over absolute maximum throughput.

Strengths
  • — Compact dimensions of 65x50mm and lightweight at 1.34 ounces
  • — High sequential read/write speeds up to 1,050MB/s
  • — IP55 water and dust resistance rating
Watch-outs
  • — Single-threaded performance falls slightly below quoted maximums
  • — Requires USB 3.2 Gen 2 port for optimal speeds
$219 · Check Price on AmazonFull review →

Specs side-by-side

SpecCorsair EX400U (1 TB)Crucial X9 Pro
InterfaceUSB4 (40Gbps)USB 3.2 Gen 2
Capacity1 TB1TB, 2TB, 4TB
Max Read Speed3.5 GB/sUp to 1,050 MB/s
Max Write Speed3500 MB/sUp to 1,050 MB/s
Form FactorPortablePortable SSD
NAND TypeTLCTLC
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