MB/s vs IOPS
Our final comparison is not really a “one over the other” situation like the others. This is because MB/s and IOPS are closely related, they just each tell you different characteristics of the drive. IOPS is basically the processing speed of the drive, while MB/s is seen as the information throughput. For example, small random reads will have very high IOPS but low MB/s because the drive is doing a lot of work, but isn’t outputting a ton of information. The drive is being taxed heavily, but the bandwidth is not. Large sequential reads on the other hand may give low IOPS but very high MB/s because the drive isn’t working super hard on processing but is pushing large amounts of information through.
There is a formula to convert IOPS to MB/s and vice versa which is, [IOPS * Transfer Size (KB)]/1024 = MB/s.
IOPS are generally given as “Random 4K” which are when it is going to be the highest number. MB/s are generally given as sequential.
So IOPS will tell you how well the drive does with small random data, and MB/s tells you how it does with large sequential data. Which stat is more important again depends on what you want to do. Refer back to the sequential vs random page for a refresher.
Conclusion
So now you know what every spec and stat means on all the SSDs you are looking at. But does that mean the choice is obvious? No, probably not. Keep in mind what you plan on doing with the drive. Is it a small boot drive (40-64GB), is it a large primary drive (128-512GB w/ OS installed on it), is it a super fast secondary storage drive (no OS installed), … I think you get the idea here. Don’t just look at the specs on Newegg and assume that since the numbers there are higher it is better than a different drive. This is where review sites such as ours really come in to play. You need to get the whole picture before you can make a well informed decision. Choose a drive that suits your needs and budget and you won’t be disappointed.
Good post guys, very informative for people who don’t know that much about SSD’s!