The write tests are usually flawed, because disks will cache writes and say "yes yes I got it" even if it's not been written to disk yet, so they're a lot more difficult to judge accurately. Because the test file is not that large it. It also helps if several blocks are read from the same track (no seeking, and you can read the first block coming under the read/write head). The included RMPartUSB.exe is called and runs the test by reading from and writing to a file of around 63MB in size. For instance, the seek time is shorter when going from track 1 to track 2 than from the first to the last, so ordering the reads on increasing tracks saves time. It uses both sequential and random (with different block sizes) tests. What it does App performs number of repeated tests (five by default) on selected drive partition and reports read and write performance. It tests drives for read and write speeds. This enables the drive to reorder the reads so they're less random. I had previously posted about CrystalDiskInfo and this one is another utility from same developer. The Q32T1 test leverages queuing: multiple read commands (up to 32) are sent to the drive before waiting for the results (and as soon as a result comes back, a new read is requested, maintaining a queue of 32 pending reads). Sequential Write : 87.305 MB/s Random Read 512KB : 41.564 MB/s Random Write 512KB : 81.893 MB/s Random Read 4KB (QD1) : 0.857 MB/s 209. That's for the RND4K Q1T1 read test (bottom left of your first screenshot), which is the ultimate random read test, with each read waiting for its results before getting to the next one. So the results of the benchmark are actually slightly better than theory! With 4K blocks as used by the benchmark, that's 228 KB/s, or 0.228 MB/s. Which in turn means a bit under 57 reads per second. That means that on average, reading a random block will take 17.6 ms (not counting command processing and the data transfer itself, but that's usually peanuts in comparison).
Crystaldiskinfo test speed read wirte Pc#
Disks come in a variety of speeds, from 5400 RPM (revolutions per minute), which is quite standard for the smaller consumer 2.5" disks, up to 15000 RPM for high-end enterprise-grade disks.Īt 5400 RPM (which means 90 revolutions per second), it takes on average 5.6 ms for the right block to be under the read-write head. The Western Digital PC SN530 NVMe SSD 512GB, M.2 2280 (SDBPNPZ-512G) is a mid-range NVMe drive using Toshiba/WD 3D-NAND TLC with 96 Layers. For this specific disk, it's 12 ms.Īverage random rotational latency is directly dependent on drive rotation speed. The platter needs to rotate until the right "sector" or block is under the read/write head ( rotational latency).Īverage random seek times are usually somewhere between 9 and 15 ms, depending on the disk. The head needs to be moved to the right "track" along the radius of the platter ( seek time). To read a random block on the disk, two things need to happen: A hard disk drive is made of platters that turn at the specified speed, and read-write heads which move along the radius of the platter.
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