Meausuring QD in win7

[Levish]

they don't "keep the qd low", their latency is so low (.1ms or less compared to 12ms) that they can find and retrieve anything small before the normal drives could even find them. This is also why if you work with mostly large files SSD's will not be a major benefit.

At a QD1 of 1 with small files (below stripe size) you will have single SSD speed. At a QD of 2 with a large file you will have however many drives worth of performance that the file is striped across (i.e. a 128k stripe will go across 2 drives for a 256kb file, 4 drives for a 512kb file etc). But this isn't entirely realistic since its possible that the 2nd 4k file might be on one of the other disks in real useage.

But I believe you pay for using too low a stripe by incuring extra IOPs on the controller/CPU and drive so there are no free lunches.

*side note*

ideally if you want to look at disk information that windows provides you want to use performance monitor (aka system monitor) and load up the respective counters or creat a new counter log for physical or logical disk (whichever you are interested in measuring).