Hi!
In theory NCQ should speed up things when multiple threads/taks/processes/programs are accessing the hard drive, right ?
But I see the opposite.
My mainboard (details below) can run its ICH9R SATA adapter in legacy or AHCI mode.
I noticed, that in AHCI mode (it allows NCQ, as opposed to legacy mode) I get huge (reproducible) slowdowns.
I did the following test procedure:
Preparations
- create a test directory , like : md C:\src
- put two large (gigabyte) files in it ([1])
- create a destination directory, like : md c:\dest
Test run:
- reboot (to make same conditions for each test run)
- open a command prompt (cmd.exe)
- run the command : copy c:\src c:\dest
- while the copy is running, open the start menu and start Wordpad
- after Wordpad starts, close it
- from the start menu start (and again immediately close) also: Notepad, Calculator, Paint
(They are all under "All Programs"/"Accessories")
(note: do this while the copy is running)
Measure the time it takes to start each program (no need for a clock, counting seconds in your head is more than enough).
What happens on my system is this :
- in legacy mode, each program starts in a seconds (Wordpad, being larger, takes 3-5 seconds)
- in AHCI mode, it sometimes it takes 2 seconds, sometimes it takes a minute ! Often, it takes 10 seconds just for the Start submenus to open.
I tried several operating systems: Windows 2003 Enterprise, Vista Enterprise, Windows XP Professional SP2, Windows 2008 x64
In all cases: legacy mode works smooth, AHCI mode have the "minute to start wordpad" problem.
Driver used:
- for legacy mode : Windows builtin Standard IDE driver
- for AHCI mode :
-- Windows XP and 2003 : Intel Matrix Storage Manager v7.8
-- Windows 2008 and Vista : msahci.sys (Windows builtin AHCI driver)
-- Vista : also tried Intel Matrix Storage Manager v7.8
There was only one exception to the "AHCI is much slower" result: Windows XP Pro SP2, updated to SP3, then cloned to another partition and finally changed from legacy mode to AHCI (by: force install the intel driver, reboot, change setting in BIOS, boot Windows)
In this case, I did not see the problem.
I contacted MS newsgroups, Asus support, Intel support. But no useful response. (Intel said : We have not replicated such issue nor have other customers reported it.) Talks with Asus are ongoing.
Did anyone experience this ?
Solution ? Just run in legacy mode ?
Regards,
David
[1] - I used the two freely downloadable iso images from this page : Windows Server 2008 Trial Software
My system details:
mainboard : Asus P3K-E WiFi AP , BIOS version 1013, Intel P35 & ICH9R chipset
CPU: Intel Q6600 (not overclocked)
RAM: 4x2GB DDR2-800 (Transcend JM800QLU-2G)
gfx: Gigabyte GV-NX88T512HP/typeA
HD: Western Digital WD7500AAKS - connected to one of the ICH9R SATA ports
optical: Samsung SH-S203P - connected to one of the ICH9R SATA ports
(problem same even if I disconnect the optical unit)