Silicon Power Slim S55 SP240GBSS3S55S25 240 GB

Historical digression

Silicon Power Slim S55 is the most "veteran" and at the same time the most "mysterious" SSD on the market. Its first version went on sale back in 2014 and was built on the then popular SandForce SF-2281 controller. This was followed by variations with the more advanced Phison S8 and S9 controllers, which learned to work equally fast with compressible and incompressible data. Last year's versions were already based on Phison S10 and Silicon Motion SM2246, which was caused by the transfer of S55 from MLC to TLC memory (previous controllers simply did not support it).

Thimblerig

Finally, the latest iteration of the 2018 Silicon Power Slim S55 switched to 3D TLC memory (slightly faster than planar TLC) and three controllers at once: Silicon Motion SM2258, Phison S11 and Marvell 88NV1120. Their common characteristic is "bufferlessness": each of them, of course, has a small cache, but they are not supplemented with an external RAM-memory chip in order to save money. Line speeds are also about the same: an average of 460 and 370 MB / s for reading and writing.

The less you know the better you sleep

But the mechanisms of SLC caching are significantly different. So, in Silicon Motion SM2258, the volume of the SLC cache is 30 percent of the volume of the drive (when the cache overflows, the write speed drops to 100 MB / s). Whereas the Phison S11 and Marvell 88NV1120 have a strictly fixed cache size of 4 GB. Moreover, it is impossible to distinguish different versions of Silicon Power Slim S55 by appearance or marking — it turns out a kind of lottery. In justification, we can say that for the entire time it has been on the market, the S55 has been, is and, apparently, will be one of the most affordable SSDs, and with a surprisingly low percentage of defects (apparently, Silicon Power has well-established quality control in production). And for an undemanding average buyer, there is by and large no difference between the controllers.