Write Intensive Usage

When copying games from your Steam Library or other very large files (>10 GB), you might have noticed that write speeds on your SSD start out at full speed and then drop considerably. The underlying reason is that modern drives have caches that soak up write bursts to improve performance. In the fairly uncommon scenario of writing data that's too big to fit into these caches, the drive will have to write data directly to flash, and it will probably juggle some out of its write cache at the same time, which can result in a significant loss of write speed. Newer TLC drives use part of their capacity in SLC mode for increased performance. This test can reveal the size of that SLC cache.

Testing on this page looks at exactly that scenario. We write a sequential stream of 1 MB blocks to the drive in a single thread, like a typical file-copy operation would do, and measure write speeds twice a second. The drive is fully erased before testing to ensure any caches are emptied. Please note that this test writes a lot of data in a very short time, which is something most consumers will never do.





Very interesting! Both MLC and TLC variants show nearly the same write performance, and it's impressive in both tests. While we'd expect a nearly straight line for the MLC model because writing to MLC is fast, most affordable TLC drives will show a significant loss in write performance once their cache is exhausted. This isn't the case with the TLC variant—speeds remain constant as we fill the drive, which is an excellent result. While there's a small 12 MB/s difference between MLC and TLC, it isn't significant enough to impact real-life performance in any meaningful way.

If you've previously been burned by the TLC write hole on SSDs (some performance drops to below HDD speeds), this drive could be a great option. It provides very consistent write speeds that are not far from the maximum the SATA interface can provide.

Take a look at the chart below—sustained writes are better than some NVMe-based SSDs!