Benchmark Results: Incompressible Performance
SandForce's SF-2281 controller handles compressible data very efficiently, and the preceding page illustrates its best-case behavior nicely. However, the controller vendor openly admits that performance drops when it comes to addressing incompressible information. The proprietary DuraClass engine was designed under the assumption that most data is compressible. However, there are still plenty of workloads that involve incompressible information, too.
Incompressible Random Writes
All of the SandForce-based SSDs deliver between 70-80 MB/s when they're presented with incompressible data at a queue depth of one. Intel's SSD 330 starts at the bottom end of that range. It visibly suffers from whatever Intel did to handicap its performance.
From fastest to slowest, these SSDs are ranked in the following order:
- 240 GB SSD 520 and 240 GB Vertex 3
- 180 GB SSD 330
- 180 GB Agility 3
- 120 GB Vertex 3
- 120 GB SSD 330
- 120 GB Agility 3
- 60 GB SSD 520 and 60 GB Vertex 3
- 60 GB SSD 330 and Agility 3
The SSD 330 trails behind the SSD 520 and Vertex 3, as expected.
When it comes to comparing SSDs at similar capacity points, it is surprising to see the SSD 330 outrun OCZ's Agility 3. In fact, we notice that a higher-capacity mainstream product can actually outperform a smaller performance-oriented model. Here, it's the 180 GB SSD 330 delivering better benchmark results than the 120 GB Vertex 3.
Incompressible Sequential Write Performance
Performance in incompressible sequential writes falls the same as it did in the preceding graph. The main difference here is that queue depth has almost no effect on measured performance.