Sequential Performance Versus Transfer Size
Alright, so that was 128 KB sequential performance in Iometer with the RevoDrive 3 X2 operating on data with a queue depth of one. As we've already established, though, that's not the type of environment this product is intended to address. If you're shopping for a PCI Express-based SSD, it's because you need unparalleled throughput, and you have a workload able to tax the storage subsystem with a higher number of outstanding requests.
This time we'll use ATTO to test the sequential reads/writes over 2 GB using a queue depth of two. Why only a queue depth of two? Even when you're pushing the envelope, operations complete so much faster on an SSD that queue depths higher than two or three are far less common on an average desktop.
The other reason to use ATTO is its ability to easily test different transfer sizes. While 128 KB is the standard block size for measuring sequential performance, there are situations where you're going to deal with smaller or larger transfer sizes. Think about executables or video files. The block sizes are often larger than 1 MB. On the lower end of the spectrum, DLLs and file dependencies are often 4 KB or less.
Using a queue depth of two, there's very little performance difference between the RevoDrive 3 X2 and other SSDs at smaller transfer sizes. In fact, in some cases, the RevoDrive X2 actually outpaces the RevoDrive 3 X2 at 128 KB, 256 KB, and 512 KB. The RevoDrive 3 X2 doesn't hold a commanding lead until you get to transfer sizes above 1 MB.
Sequential write performance is a little better. Once you move up to transfer sizes above 64 KB, the RevoDrive 3 X2 holds a commanding lead every step of the way. At 1 MB, you're looking at an amazing sequential write speed of 900 MB/s.
Turning up the queue depth to four gives us a different look at performance. The RevoDrive 3 X2 offers slower performance at lower transfer sizes and at 128 KB, but at transfer sizes above 256 KB, you're pushing sequential read speeds in excess of 1 GB/s.
In sequential writes, the RevoDrive 3 X2 still suffers at lower transfer sizes. However, you only need a 64 KB transfer to see throughput close to 1 GB/s.