#Sequential testing at intel full

The enterprise-focused Optane SSD P4800X is slower than the consumer Optane Memory for sequential writes of less than 4kB, and even the Samsung 960 EVO beats the P4800X at 512B transfers. These tests were conducted on the Optane Memory as a standalone SSD, not in any caching configuration. Each sub-test (transfer size or queue depth) is run for four minutes and the performance statistics ignore the first minute.

For testing a range of queue depths, a 128kB transfer size is used and up to four worker threads are used, each writing sequentially but to different portions of the drive. The sequential write performance of different transfer sizes is conducted with a single thread operating at queue depth 1. The sequential write tests are structured identically to the sequential read tests save for the direction the data is flowing. For mean and median latency the Optane Memory and the Samsung 960 EVO are relatively close, but for the 99th and 99.999th percentile metrics the 960 EVO is mostly slower than the Optane Memory by about the same factor of two that the P4800X beats the Optane Memory by. Since all four drives are saturated through almost all of this test, the latency graphs are fairly boring: increasing queue depth increases latency.

The Crucial MX300 delivers far lower performance than SATA allows for, due to this test being multithreaded with up to four workers reading from different parts of the drive. The flash SSDs are mostly saturated from the start. The two Optane devices saturate for sequential reads at QD2, but the Optane Memory experiences a much smaller jump from its QD1 throughput. The Samsung 960 EVO and Optane Memory start out with QD1 sequential read performance and latency that is relatively close, but then at higher queue depths the Optane Memory jumps up to a significantly higher throughput. Each thread is reading sequentially but from a different region of the drive, so the read commands the drive receives are not entirely sorted by logical block address. Queue Depth > 1įor testing sequential read speeds at different queue depths, we use the same overall test structure as for random reads: total queue depths of up to 64 are tested using a maximum of four threads. The three PCIe drives show similar growth through the small to mid transfer sizes, but the Optane Memory once again has the highest performance for small transfers and higher performance across the board than the Samsung 960 EVO. Each transfer size was used for four minutes, and the throughput was averaged over the final three minutes of each test segment. The test of sequential read performance at different transfer sizes was conducted at queue depth 1. This may limit how much prefetching of user data the drives can perform on the sequential read tests, but they can likely benefit from better locality of access to their internal mapping tables.

#Sequential testing at intel full

The drives were preconditioned with two full writes using 4kB random writes, so the data on each drive is entirely fragmented. Real-world sequential transfer sizes vary widely depending on factors like which application is moving the data or how fragmented the filesystem is. Sequential access is usually tested with 128kB transfers, which is large enough that requests can typically be striped across multiple controller channels and still involve writing a full page or more to the flash on each channel.