Crucial V4 256GB SSD Review – All Is Not SATA 3 Just Yet


ATTO Disk Benchmark is perhaps one of the oldest benchmarks going and is definitely the main staple for manufacturer performance specifications. ATTO uses RAW or compressible data and, for our benchmarks, we use a set length of 256mb and test both the read and write performance of various transfer sizes ranging from 0.5 to 8192kb. Manufacturers prefer this method of testing as it deals with raw (compressible) data rather than random (includes incompressible data) which, although more realistic, results in lower performance results.

Considering that posted specifications for performance are 230MB/s read and 190MB/s write, our ATTO high results of 277MB/s read and 237MB/s write are excellent for this SSD.


Crystal Disk Benchmark is used to measure read and write performance through sampling of raw (0/1 Fill/compressible) or random data which is, for the most part, incompressible. We tested in both compressible and incompressible samples and the results were virtually identical.


Up until recently, AS SSD was the only benchmark created specifically for SSD testing and it uses incompressible data.  AS SSD, for the most part, gives us the worst case scenario in SSD transfer speeds because of its use of incompressible data and many enthusiasts like to AS SSD for their needs.

CDM and AS SSD give us our first glimpse of the low 4k random write performance of 47MB/s which is substandard in today’s SSD arena.  The disk access time shown on AS SSD is excellent and will result in quick system start up times.


  1. They sold a Indilinx barefoot controlled M225 had similar performance to this drive even at sata2, can’t understand the thinking behind this drive at all. Phison ere great controllers anyway. Have a good day Les.

  2. Missed a few letters there, meant to say Phison weren’t great controllers anyway. Where’s the edit button.

  3. How about doing a summary of the best SATA2 SSDs, if one needed one today?

  4. I’m afraid I’ve gotten a little lost in the technical details here, if someone doesn’t mind helping a brother out! I have a 2008 white Macbook (SATA) and want to upgrade to SSD. Is there a reason why I would pick the V4 over the M4 if not for a slightly cheaper price at this time? Or is there some reason I should consider the M4 over the V4? And, do I need any special mounting hardware or will it plug into the existing slot in my laptop?

    • m4 is sata3 which is backwards compatible with sata 2. sata 2 itself is backwards compatible with Sata1. if your mac is sata1 you should go with v4 and not m4

  5. I’ve just purchased thw 256GB model and installed as an OS drive on my Macbook and it has worse performance than a HDD. Try multitasking with real world use and you’ll see how dire the drive is.

  6. The V4 256gb version is HORRIBLE at multitasking and cannot perform a replay service which is a relatively lite read sample, smoothly! I am hugely disappointed with this ssd.

  7. I was shocked at the performance of this V4 SSD. It is very similar to a spinning HDD and is the slowest SSD I have encountered. Shame on Crucial for ever releasing such a dullard.

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