A LOOK AT COMPRESSIBLE DATA PERFORMANCE
There are a variety of methods to look at compressible data performance with respect to LSI SandForce processors. The performance at different levels of data compressibility is governed by the processor, firmware, and the type of flash employed. For instance, drives using asynchronous flash suffer when reading incompressible (random) data while SSDs with synchronous or toggle NAND aren’t really affected.
Random data write speed is also largely governed by flash speed and type, but under random data writes, newer SandForce drives with synchronous or toggle flash are competitive with non-compressing controllers. Since most data is not 0% compressible (all zeros for example) or 100% (completely incompressible), the SF processor can more than make up the difference as most data fall somewhere in the middle. For instance, the Windows folder is almost exactly 47% compressible, which means that the compressed data is 47% of the original size. Skyrim is composed of more incompressible data, or rather data which is already compressed to some degree. It can only be compressed to 80% of it’s original size.
The read performance chart shows the HyperX 3K’s read speeds at sequential and random transfer sizes. Using data with different compression levels has very little effect on the synchronous NAND-equipped 3K. All levels of data compression, from least compressible to most compressible, are handled with effectively the same speed.
The write compression tests show that QD1 and QD4 random write performance is mostly the same. Sequential writes and QD16 random writes are dependent on easily compressible performance for the highest performance. Considering that even at it’s worst, the 3K still has a lot of bandwidth to offer. But when data is easily compressible, the 3K’s SandForce compression technology really hits the afterburner on writes.