We've talked about the new IMFT 20nm flash on a few occasions already. This is the second review we've published with the Crucial M500, the first being the 960GB model. In the highest capacity size the M500 is a very good drive with good read and write performance. The 120GB model can read data well, but its write performance is worse than most of the 128GB class SSDs that were native SATA II.
The problems don't stop there, but the reasons for more criticism is the same - the flash. Looking back at the HD Tach test where we measure sequential performance after a few light random writes, the performance drops below 20MB/s. We run this test much differently from what most review sites do. Others fill the SSD multiple times with 4K writes, a test pulled from enterprise products. We don't feel that is an appropriate way to test consumer SSDs because you will never fill your drive over and over with 4K data and not send a TRIM command. Still, the Crucial M500 120GB acts as if we beat it down with a baseball bat, riot style after what we consider an appropriate load.
Other issues include high write latency, as you can see above. If you write more than 7% of the flash capacity, the drive begs for mercy. This is something we experienced while preparing the drive for the data on disk test, first hand.
These issues don't plague the 960GB M500, but you'll have to wait for our review of the 240GB and 480GB capacity sizes to see how the new 20nm ONFi flash reacts in the middle capacity sizes.
At the time of writing the M500 120GB costs around $125. For the same price you can purchase an ADATA SX900 128GB. ADATA moved the SX900 over to Toshiba Toggle flash to sidestep the 20nm IMFT flash issues, and it also delivers longer battery life in a notebook.