Thunderbay Mini with SSDs: Incompressible Data

OWC Thunderbay Mini

Thunderbay Mini configurations start at about $379 without drives. Thunderbay Mini RAID-5 edition also available.

To increase the lifespan of the flash memory, Sandforce-based SSDs compress data.

Data compression in an SSD reduces write performance when the data is incompressible (JPG, compressed PSD or TIF, most video, encrypted data, etc).

Many other SSDs do not compress data, but also require TRIM (not needed for Sandforce SSDs). It’s a total performance picture that must be assessed: performance under one’s own actual working conditions along with longevity.

In MPG’s multi-year experience with OWC SSDs (Sandforce-based), real-world performance has been excellent (e.g. Photoshop), and lifespan has never been a concern.

Worse case performance: incompressible data

disktester fill-volume --xfer 128M --pattern randomblock

The graph below shows performance with RAID-0, RAID-5 and single SSD for highly compressible data (zeroes) vs worst-case incompressible random data.

As can be seen, incompressible data takes a substantial toll on write performance, but has negligible effect on read performance. See the red bars for each.

Since many types of data are written once and read many times, the impaired write performance is of no consequence. Moreove, real world tasks can shine even when there is heavy write activity (see the Photoshop diglloydHuge results).

See also the results with the OWC 960GB Mercury Electra 6G SSD, which is much faster.

Toggle compare single SSD vs RAID-0 vs RAID-5.

OWC Thunderbay Mini performance: Photoshop scratch disk vs MacBook Pro Retina 1TB internal SSD