AHCI and Test Setups

AHCI is a Good Thing

A surprising number of people out there do not realize that in order for your system to see the advantages of Native Command Queuing, changes must be made to the system configuration.  The X25-M is one of the best demonstrations of the gains to be had.  Current Intel SSD owners / potential buyers might want to take note of the following benches.  The huge increase in small file performance makes the effort of switching your BIOS settings to AHCI mode and installing that extra driver on your Windows install well worth the effort.  This is one of those things you want to get right the first time (i.e. before you install your OS).  If you are running XP (and possibly Vista), juggling your AHCI BIOS settings may not work, and will likely cause your system to Blue Screen on boot.  For those sufficiently savvy, PCPer forum moderator Ned Slider has posted a guide for switching to AHCI ‘on the fly’.

Long-term performance analysis of Intel Mainstream SSDs - Storage 20
X25-M with AHCI disabled (BIOS in ‘IDE’ mode).

Long-term performance analysis of Intel Mainstream SSDs - Storage 21
NCQ in action (BIOS in ‘AHCI’ mode).

While there are only small gains in large file throughput (near the bottom), there is a 2-3x improvement in small file access.  The drive also ‘ramps up’ to full speed much faster, approaching 250MB/sec when performing random 8KB reads.

Testing Setup

This will not be your typical review article, and as such we did not stick with any single testing machine.  The dynamic nature of the X25-M wear leveling / write combining routines required extensive testing over several months time.  I continued working through an upgrade of my own rig, while Ryan crunched away using his pair of X25-M’s.

Hard Drive Test System Setup


Intel Q9550  Intel Core i7 920  Intel Core 2 Duo E6400


Asus P5B Deluxe

 Asus P6T  Gigabyte P35-DS3R


4GB DDR2-800

 6GB DDR3-1600  OCZ Technology 2 x 2GB DDR2-800

Hard Drive

 Intel X25-M 80GB SSD
WD VelociRaptor 300GB WD3000GLFS
WD Raptor 74GB

Intel X25-M 80GB SSD
WD VelociRaptor 300GB WD3000GLFS
Western Digital Raptor 150GB  

Sound Card

Asus Xonar DX  Asus Xonar D1


Video Card

 EVGA Geforce GTX 260 Core 216

ATI Radeon X800 XL 

Video Drivers

Geforce 180.48

 Geforce 181.22

Catalyst 8.3

Power Supply  Corsair 620HX  Antec TruePower 480 watt

DirectX Version



Operating System

Windows XP SP3

Windows XP X64 SP2 

Windows Vista x64 SP1 

My X25-M is retail while Ryan’s are pre-release units.  Any potential differences were negated by the fact that Ryan’s are flashed with the same retail v8610 firmware.

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