Independent tests of Kioxia’s 4 TB Exceria G3 SSD show how differently it can handle a short transfer and a long one. In a November 10 review, ComputerBase found that the drive could write hundreds of gigabytes at high speed when empty, but slowed to about 300 MB/s after its fast cache filled. An earlier Igor’s Lab test found a similar slowdown under a different workload. ComputerBase’s German-language findings were summarized with AI translation, which may not be fully accurate.
Kioxia introduced the 4 TB model in June as part of its consumer PCIe 5.0 lineup. It lists sequential speeds of up to 10,000 MB/s for reads and 9,600 MB/s for writes under its test conditions. The drive uses the M.2 2280 form factor. The reviewers identified QLC flash, which stores four bits per cell. For faster writes, the drive temporarily uses some of that flash in a mode that stores one bit per cell. The available space for this cache can shrink as the drive fills.
ComputerBase repeatedly copied 10 GB files from a RAM disk to a Kioxia-supplied sample on a Ryzen 9 7900 system running Windows 11, using a motherboard heatsink and a fan. It recorded more than 5,000 MB/s for about the first 800 GB on a freshly formatted drive. The fast portion was about half as large when the drive was already half full. After the cache filled, write speeds fell to roughly 300 MB/s in the test.
Igor’s Lab used an Intel Core Ultra 7 270K Plus system with Windows write caching disabled and a motherboard heatsink. In its continuous write test, a nearly empty drive began to slow after about 815 GB had been written. The reviewer reported roughly 6,509 MB/s in the fast portion and 279 MB/s in the section after the transition. The test detected a later thermal change. The two labs used different platforms and workloads, so the figures describe their own tests. Neither test establishes a fixed cache size or write speed for every system.
The results are most relevant to jobs that keep writing after the cache fills, such as large local backups or moving a sizable media library. Shorter transfers can finish in the fast portion. The PCIe generation describes the drive’s connection to the system. Sustained write speed also depends on the flash, available cache and test conditions.
Editorial Opinion
For a working drive that regularly takes large video imports or disk images, the useful benchmark is how long the fast phase lasts when the drive is already in use. Reviewers should publish both the fast and post-cache speeds at multiple fill levels. That would give readers a better basis for deciding whether the capacity and peak speeds fit their workloads.
References
Günsch, M., & Timm, J.-F. (2026, November 10). Kioxia Exceria G3 4 TB im Test: Ist PCIe 5.0 im Mainstream wirklich schneller als PCIe 4.0? ComputerBase.
Kioxia. (2026, June 16). Kioxia introduces 4 TB model to PCIe 5.0 personal SSD product line [Press release].
Kioxia Europe. (n.d.). EXCERIA G3 NVMe SSD [Product specifications].
Wallossek, I. (2026, October 12). KIOXIA EXCERIA G3 4 TB review: How much SSD is behind PCIe 5.0? Igor’s Lab.
Have a factual correction or website problem? Contact PartialMedia with the article link, disputed passage and supporting source.
Discussion
Comments load automatically through Disqus. This connects to Disqus and its partners, which may use cookies and process your IP address and browser information. Disqus privacy policy.