I am a beginner of hardware. I find two series of SSD to compare, 840 EVO and M500, because the specifications and the prices of them are approximate. Both of them use SATA 3, so you need to compare with the read speed and the write speed, if you prefer faster one. The sequential read speed of 840 is 540MB/s, and the sequential write speed is 410MB/s. M500 is slower, but the performance of M500 is great as well, its Shock-resistant design makes it more durable than 840. The most important thing of SSD is the controller, 840 uses 3-core Samsung MDX controller, M500 uses Marvell’s latest controller, maybe the second one is better. This is my poor review, how to compare them with more details, give me your advice.