This SSD uses TLC NAND memory, which is a good feature. However, it seems it lacks an internal DRAM cache, which is not very good. I'm not 100% sure tbh about the absence of the DRAM cache, it's difficult to find detailed specs for this drive, but from what I googled, it seems it doesn't have a DRAM cache. The main issue for me—and the reason I deducted one star—is that once the drive is partially filled, the write speed for large files drops to approximately 438 MB/s. When the disk is empty, CrystalDiskMark reports sequential read and write speeds of around 1 GB/s. However, CrystalDiskMark is not a good test for real-world performance, at all (I’ll explain this in more detail below). In actual use, writing large files to an empty disk achieves speeds of about 736 MB/s. As mentioned earlier, the write speed decreases noticeably as the drive fills up. While this behavior is somewhat normal for SSDs, the speed drop can be much less pronounced in more expensive or higher-quality SSDs. That said, reading large files remains consistently fast with this drive, maintaining speeds of around 1 GB/s regardless of how full the disk is. Recently, I realized I didn’t know as much about SSDs as I thought and had been relying too heavily on CrystalDiskMark for testing. Since then, I’ve educated myself on SSDs, learned how to test them properly, and even acquired several different SSDs for testing and experimentation. If you’re interested in learning more about SSDs and proper testing methods, feel free to read on. A lot of people use CrystalDiskMark for testing storage speed. You should know that using CrystalDiskMark is not a good way to test speed. It's a pretty limited test. It can't emulate the real-life use case of copying large files. Even if you choose 64 Gbyte test file size, CrystalDiskMark will simply create a 64Gb test file, but then it will only write or read a small part of that file. So if you want to copy large files with high speed, you need to test it by... no surprise here... by copying large files. Although I think it can be a surprize for a lot of people who rely on CrystalDiskMark. Make sure you will copy from another very fast SSDs, so that the read performance of that other SSD will not be the real bottle neck. I used my fastest internally isntalled NVME SSD to copy large files from (TLC NAND memory, SLC cache, DRAM cache, up to 7 Gbyte/s read & write speeds). Storage drives have different kinds of caches. SSD drives can have an SLC cache (SLC = Single-Level Cell, the fastest and most expensive type of NAND memory) and/or a DRAM cache (for example, an SSD can have 1Gb DDR4 internal cache). Consumer SSDs usually use QLC (Quad-level cell, stores 4 bits per cell, one of the slowest and less reliable types on NAND memory. Used in cheaper SSDs) or TLC (Triple-level cell, stores 3 bits per cell, faster and more reliable than QLC. Used in more expensive SSDs). You can see how an SLC & DRAM caches come into play, for example, here: https://www.techpowerup.com/review/silicon-power-xs70-1-tb/6.html More expensive SSDs also have an internal DRAM cache, which is used before the SLC cache (if present) is used. In 2024-2025 DRAM cache usually uses DDR4 memory. DDR4 cache is a few times faster than TLC for sequential reads & writes and has about a 1000x lower latency than TLC (nanoseconds vs microseconds). So when choosing an SSD, if you want high sustained write-speeds, you need to make sure the drive has the following characteristics (which often can be found in the SSD database on this website: https://www.techpowerup.com/ssd-specs/silicon-power-xs70-1-tb.d707 ): 1) TLC type of NAND memory (faster than QLC) 2) SLC Cache and the larger, the better (good drives nowadays have 100+ Gbytes of an SLC cache). You can see how an SLC & DRAM caches come into play, for example, here: https://www.techpowerup.com/review/silicon-power-xs70-1-tb/6.html 3) DRAM Cache and the larger, the better (1Gb+ DRAM cache is a good size) I'm sorry for this long text, I just hope I can help some people to understand SSDs and how to test them better and make better choices when buying SSDs and SSD adapters.
