![]() Sequential t-Test What is a sequential test procedure? ![]() This vignette describes the theoretical background of these tests.Ī general guide, how to use the package and ganeshts: The NAND part of the quoted tweet is factually wrong.The sprtt package is the implementation of sequential probability ratio tests using the associated t-statistic ( sprtt).RyanSmithAT: While I don't think there will be any surprises here, as AMD's pre-release data has been very fair, it's nice to co….RyanSmithAT: It would be weirder if it hadn't.But before I go, I had a chance to see Sapphire Rapids liv… RyanSmithAT: About to head out to the airport to catch a flight home.gavbon86: I didn't realize I hadn't subbed.gavbon86: Understandable why they've done it though.gavbon86: Not sure it's "king", but a good motherboard review nevertheless via gavbon86: Go on, try and sell me one.Why do I need it?.It used to only be possible to see these numbers on PCIe SSDs that leveraged multiple controllers. At a higher queue depth the P3700's performance scales even further. The result is a pretty big reduction in sequential write speed on SandForce based controllers. The AS-SSD sequential benchmark uses incompressible data for all of its transfers. AS-SSD Incompressible Sequential Read/Write Performance Once again comparing the P3700 to the old X25-M G2 we see 15x the performance in 6 years. The P3700's 18-channel controller and firmware do a good job of splitting up write requests across as many parallel die as possible. We typically never see this sort of performance at a queue depth of 1. Sequential writes are even more impressive. Once again we see the P3700 does extremely well at low queue depths, here its sequential read performance is substantially better than anything else. The results reported are in average MB/s over the entire test length. To measure sequential performance we run a 1 minute long 128KB sequential test over the entire span of the drive at a queue depth of 1. ![]() Random read performance is better than anything else here, but there's a limit to how much parallelism you can extract from a low queue depth random read workload. I also included the old X25-M G2 to show just how far we've come - the P3700 is nearly 15x the speed of Intel's first generation MLC SSD controller.Īt a higher queue depth the Z-Drive R4 is able to catch up to the P3700, but being able to deliver excellent random IO performance even at low queue depths is a staple of a good client drive. Here the P3700 is more than twice as fast as the closest SATA competitor, which is amazing despite the low queue depth of our test. Our enterprise look at the P3700 focused on steady state 4KB random write performance, but surprisingly enough our short burst/8GB LBA space testing puts the P3700 at a very similar performance level. The results reported are in average MB/s over the entire time. We perform three concurrent IOs and run the test for 3 minutes. ![]() Our first test writes 4KB in a completely random pattern over an 8GB space of the drive to simulate the sort of random access that you'd see on an OS drive (even this is more stressful than a normal desktop user would see). Random accesses are generally small in size, while sequential accesses tend to be larger and thus we have the four Iometer tests we use in all of our reviews. The four corners of SSD performance are as follows: random read, random write, sequential read and sequential write speed.
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