Here I will publish some tests of speed to compare firmwares. You can offer any methods to test speed of DNS-300.
Current HDD is Seagate 120Gb. Usual speed of this HDD is 60Gb per second on read in PC.

The best results for HDD are:
write - 5.66 Mb/s
read - 8.24 Mb/s

root@DNS-300:/# hdparm -t /dev/hda

/dev/hda:
 Timing buffered disk reads:  64 MB in  6.50 seconds =  9.85 MB/sec
root@DNS-300:/# hdparm -T /dev/hda

/dev/hda:
 Timing buffer-cache reads:   128 MB in  4.10 seconds = 31.22 MB/sec
root@DNS-300:/# hdparm -t /dev/hda

/dev/hda:
 Timing buffered disk reads:  64 MB in  6.15 seconds = 10.41 MB/sec
root@DNS-300:/#

root@DNS-300:/home# time dd if=/dev/zero of=test bs=1024 count=102400
102400+0 records in
102400+0 records out

real    0m17.660s
user    0m0.660s
sys     0m14.800s

root@DNS-300:/home# time dd if=test of=/dev/null bs=1024
102400+0 records in
102400+0 records out

real    0m12.130s
user    0m0.450s
sys     0m8.100s