O Relatório Tech analisou a série Samsung 840 e concluiu com:
Those expecting the Samsung 840 Series to be a true successor to the 830 Series will no doubt be disappointed. The new drive is slower than its predecessor overall and quite sluggish with both sequential and random writes. Samsung's use of TLC memory is almost certainly to blame for the slower write performance, but the firm hasn't bet the farm on triple-stuffed NAND. The 840 Pro is the true follow-up to the 830 Series, and it features MLC chips with two bits per cell. Of course, the Pro also costs 50% more than the 840 Series. Clearly, it's a different class of drive.
Pessoalmente, eu pegaria o 830 sobre o (não-profissional) 840.
Você pode ler a crítica completa aqui .