In SATA2, it helps out well (on noiseless computer)

Starting your computer (E6600 2.4GHz processor - 8 Gio RAM - Ubuntu Studio 12.04 - 64-bit) in 23 seconds between pressing the power button, and the login window.

$ Sudo hdparm -t --direct / dev / sda
/ Dev / sda:
Timing O_DIRECT reads disk: 652 MB in 3.00 seconds = 217.16 MB / sec

$ Sudo hdparm -t / dev / sda
/ Dev / sda:
Timing buffered disk reads: 548 MB in 3.00 seconds = 182.62 MB / sec

sudo -i smartctl / dev / sda
smartctl 5.41 2011-06-09 r3365 [x86_64-linux-3.2.0-82-lowlatency] (local build)
Copyright (C) 2002-11 by Bruce Allen, [...]

=== === START OF INFORMATION SECTION
Device Model: Crucial_CT128MX100SSD1
Serial Number: ------------------------
LU WWN Device Id: ------------------------------
Firmware Version: MU01
User Capacity: 128,035,676,160 bytes [128 GB]
Sector Sizes: 512 bytes logical, physical 4096 bytes
Device is: Not in smartctl database [for details use: -P showall]
ATA Version is: 8
ATA Standard is: ATA-8-ACS revision 6
Local Time is: Fri 1 May 2015 10:29:08 p.m. EST
SMART Support is: Available - device HAS SMART capability.
SMART Support is Enabled

I do not know why it does not go faster even SATA2.