On 08/01/12 07:30, Marc MERLIN wrote:

2) Then I put a crucial 256 C300 SSD (the replacement for the one I 
had that just died and killed all my data), and du took 0.3 seconds on 
both my old and new thinkpads. 

What does FIO say on your Samsung 830 SSD, 4k random reads?
Last time I checked online benchmarks Samsung 830 had very good 4k 
random reads, but it's difficult to find online benchmarks for 
incompressible data (which fio rightly uses btw)

multithreded test:
vi fiotest_mt.fio
         [random-read]
         rw=randread
         numjobs=20
         thread
         iodepth=10
         group_reporting
         blocksize=4k
         size=512m
         directory=/mnt/<yourmountpoint>
         end_fsync=1
         runtime=10

and single threaded (more important here):
vi fiotest_st.fio
         [random-read]
         rw=randread
         numjobs=1
         thread
         iodepth=1
         group_reporting
         blocksize=4k
         size=4g
         directory=/mnt/<yourmountpoint>
         end_fsync=1
         runtime=10