Q.)  A partner student is asking the question, which type of discs have the best performance in the P6000?  SSF 15K or LFF 15K ?

A.)  Take a look at page 9 of the  document:  http://h20195.www2.hp.com/v2/GetPDF.aspx/4AA3-2517ENW.pdf

Here are some quotes which basically support  the thesis that LFF drives are more performing than SFF drives. Even seek times, which should be better on SFF drives due to smaller geometry are better on LFF due to better mechanics:

Performance numbers for SFF and LFF drives, on a drive-per-drive basis, are very similar for the same drive type. That is, a 10k rpm SFF drive versus a 10k LFF rpm drive or a 15k SFF drive versus a 15k LFF drive have similar drive performance specification numbers. 

15k rpm drives’ average rotational latency time is less than 10k rpm drives’ rotational latency time, which is less than 7.2k drives’ rotational latency time. That translates to faster performance for the higher speed 15k rpm drives

Seek times, both read and write, vary by drive family. For example, the 300/450/600 GB LFF 15k drives’ seek times are slightly faster than the 300/450/600 GB SFF 10k drives.

– (While SFF drives have smaller distances to move the data heads because of their smaller size, the positioner mechanisms in the SFF drives are not as strong as the positioner mechanisms of the LFF drives. So, even though the LFF drives have longer distances to move the data heads, they are able to move faster than the SFF drives.)