1TB Class Performance Testing
We recycled the charts from the first Black SN750 review. The heat sink version of the Black SN750 joins the original version. We also included two Samsung 970 Series models, the EVO and Pro. The two new Silicon Motion, Inc powered SM2262EN join the group, the ADATA SX8200 Pro and HP EX950. Finally, we also have the MyDigitalSSD BPX Pro.
Sequential Read Performance
The two Black SN750 and MyDigitalSSD BPX Pro have an issue with our testing script. The queue depth 2 and 4 results are lower in our test but not when measured with other software. For this reason, we will skip over the sequential read performance for this review, at least at low queue depths. At high queue depths, the WD Black SN750 matches the performance of the other drives at the upper limits of PCIe 3.0 x4.
Sequential Write Performance
As mentioned, in burst testing there will not be a deep divide between the two Black SN750 SSDs. The drives delivers excellent sequential write performance when you only need to move a small amount of data.
Sustained Sequential Write Performance
The Black SN750 uses a small SLC cache for data writes. The cache is large enough to consume random write bursts but doesn't have the same capacity as many of the other new drives with dynamic cache for extended sequential writes.
The results of this ten-minute test are what we used on the first page to determine the amount of data written between the two Black SN750 SSDs. The two show in more detail how the non-heat sink version develops performance drops when the controller reaches 80 degrees.
You can also see this on the previous chart. Users can transfer around 400 GB of data on the 1TB drive without a heat sink before throttling starts.
Random Read Performance
The Black SN750s only tiptoe past the 10,000 random read IOPS mark at queue depth 1. W would like to see more performance in this area. It will also come up later in this review when we start testing with applications.
Random Write Performance
There is a wide divide in random writes with Game Mode enabled and disabled. There are small performance benefits with the software enabled but none more than random write performance. Here we see the gap with the software running on the base SN750 and not on the heat sink model.
70% Read Sequential Performance
Most applications function as mixed workloads to the storage. The Black SN750 performs extremely well in the sequential 70% read mix test. The architecture behind the Black SN750 is far superior to others when mixing large block size reads and writes.
70% Read Random Performance
The low random read performance leads to a low random mixed performance. This test is 70% reads after all. At high queue depths, the Black SN750 performs well, but consumer workloads fall much power on the scale, where the Black SN750 is weaker.