# Improve SATA hard disk performance (Convert from IDE to AHCI)



## segalaw19800 (Aug 25, 2010)

Every hard drive in a modern computer is connected to the system through a storage controller. This controller typically can communicate with the hard drive via a number of different interface protocols. For maximum compatibility many computers are configured in the BIOS to use the older IDE interface protocol to communicate with modern SATA hard drives. This setting is acceptable for the average computer user but IDE lacks support for new technologies such as native command queuing (NCQ) and hot-plugging hard drives (add or remove drives without restarting the computers).

Intel invented a new storage controller interface known as AHCI (Advanced Host Controller Interface) that supports these new technologies with modern SATA hard drives. If you have a hard drive that supports NCQ, it is worth a try to see if your disk performance improves with your workload. 

The main problem preventing users from changing the storage interface protocol from IDE to AHCI in the past has been blue screens that could only be cured by undoing the BIOS change or reinstalling Windows. The cause of the problem is the mass storage driver installed when Windows was first setup. Since IDE was enabled at install only the IDE storage driver was configured in Windows. With the AHCI driver missing, Windows cannot read from the hard drive and throws a BSOD with error code 0x0000005B.

Now there is an easy solution that will allow you to switch between IDE and AHCI in the bios and Windows will boot without any problems. The key is to enable the AHCI driver in Windows before you make the setting change in the BIOS. 

For most users this will work:

Open Registry Editor and navigate to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\msahci. 
Right click on the Start registry DWORD and select Modify.


Set the value to 0 and click OK.


Now the Start setting should be set to 0.


Reboot and enable the AHCI setting in your BIOS. 
If you are using a RAID adapter or other interface try the following:

Open up Registry Editor and naviage to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\iaStorV OR HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\iaStor. 
Repeat the steps above. 
Not all users will see a major performance improvement with AHCI and a SATA hard drive but NCQ can be very helpful under the right workload. Post your experience and setup in the comments below.   

by:   Steve Sinchak 

link:  http://www.tweakwin7.com/articles/44119/improve-sata-hard-disk-performance-convert-from-ide-to-ahci/


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## Mussels (Aug 25, 2010)

you dont get speed boosts at all, going from IDE to AHCI. you just get some extra features like NCQ and hot swap capabilities.


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## segalaw19800 (Aug 25, 2010)

Mussels said:


> you dont get speed boosts at all, going from IDE to AHCI. you just get some extra features like NCQ and hot swap capabilities.



that true but at lease you get the added features


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## segalaw19800 (Aug 25, 2010)

my drive is running in ahci mode    no bsod yet


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## 95Viper (Aug 25, 2010)

Ah, but under the right set of circumstances, NCQ does improve preformance (not saying speed of the drive).
As, can be seen here:Native Command Queuing.

If data is located in various distributed sectors on a non-ncq HDD drive, then it must retrieve them in order, which may take more rotations of the platter, than on a ncq enabled HDD drive.

@segalaw19800> Use the search function, as there are a number of threads associated with this same topic.
But, glad you got it working to your satisfaction.


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## Fatal (Aug 25, 2010)

I enabled this a few days ago the only difference is my boot time. It takes a long time to boot now. Other than that I guess the extra features can be good.


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## $immond$ (Aug 27, 2010)

Mussels said:


> you dont get speed boosts at all, going from IDE to AHCI. you just get some extra features like NCQ and hot swap capabilities.



Ive benched my SSD in IDE and AHCI mode. I seem to get a whole 3-4 Mb/s more in AHCI mode over IDE mode. Not much of an increase but Chrystal Mark seems to show consistent results.


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## niko084 (Aug 27, 2010)

$immond$ said:


> Ive benched my SSD in IDE and AHCI mode. I seem to get a whole 3-4 Mb/s more in AHCI mode over IDE mode. Not much of an increase but Chrystal Mark seems to show consistent results.



I'm curious as to how it benchmarks..
Most drive benchmarks I have seen are not exactly accurate and realistic.


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## RejZoR (Aug 27, 2010)

AHCI really only adds NCQ feature and slightly lower CPU utilization during intensive HDD operations.
Bandwidth itself won't really change much if at all...


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## caleb (Aug 27, 2010)

Plus you get a diffrent driver [possibly newer].

Would actually try it on my dell d630 which has lame corporate OS installed without AHCI enabled but will this work for XP ?

EDIT : self answer : No such key in XP


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## filip007 (Aug 27, 2010)

AHCI and NCQ give faster write times and with some proper chipsets like ICH9R/10R/11R the new boards have this function already in i think.


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