Check if using iastor instead of msahci

It's Not Lupus

Senior member
Aug 19, 2012
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How can I check if I'm using iastor instead of msahci for my SSD? I'm using Win 8.1, but AS SSD Benchmark requires that I have .NET Framework 3.5 which probably takes up a few gigabytes. Is there any other way?
 

Fernando 1

Senior member
Jul 29, 2012
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How can I check if I'm using iastor instead of msahci for my SSD?
Open the "IDE ATA/ATAPI Controllers" section of the Device Manager and look for the listed SATA AHCI Controller.
If there is a "Standard SATA AHCI Controller", you can be sure, that the generic MS AHCI driver named STORAHCI.SYS is managing this Controller.
After having installed any Intel AHCI driver named IASTOR.SYS, you will see an Intel SATA AHCI Controller.
 

BonzaiDuck

Lifer
Jun 30, 2004
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Perhaps I should start a different thread on this topic, but what I have to say shouldn't make for extended exchanges.

Another thread on TRIM, performance and the two driver options had raised an extended discussion focused on performance. I don't think -- for performance's sake -- there was significant difference between the two drivers.

But I DID discover a difference, and it is worth explaining.

I've been converting "IDE-to-USB2" external boxes to "eSATA." Windows throws up a "Safely Remove" icon in the system tray for a USB device -- something you'd want to have if you intend to hot-swap or remove drives without rebooting the system.

The MSAHCI driver also throws up a "Safely Remove" icon if "hot-swap" is enabled for particular ports in BIOS. Of course, the context requires the ports and drives to be configured in BIOS' AHCI-mode.

The IASTOR driver does not do this, and folks (like me) might then seek a solution in "extra software" like the utility "Hot Swap!".

You don't need the extra software if you replace the IASTOR driver with MSAHCI.

AND HERE'S A FOOTNOTE FOR THOSE WHO WONDER ABOUT SUCCESSFUL DRIVER REPLACEMENT: You only need to enter "Control-Panel->Programs&Features" to uninstall the "Intel Rapid Storage Technology [IRST]" software. You will need to reboot the system twice: first, to complete the IRST removal, and second -- to complete the MSAHCI installation. Everything should be wonderful. If you were using Samsung Magician manage an SSD, the driver replacement will have no effect on RAPID or anything else . . .
 
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Micrornd

Golden Member
Mar 2, 2013
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But I DID discover a difference, and it is worth explaining.

I've been converting "IDE-to-USB2" external boxes to "eSATA." Windows throws up a "Safely Remove" icon in the system tray for a USB device -- something you'd want to have if you intend to hot-swap or remove drives without rebooting the system.

The MSAHCI driver also throws up a "Safely Remove" icon if "hot-swap" is enabled for particular ports in BIOS. Of course, the context requires the ports and drives to be configured in BIOS' AHCI-mode.

The IASTOR driver does not do this, and folks (like me) might then seek a solution in "extra software" like the utility "Hot Swap!".

You don't need the extra software if you replace the IASTOR driver with MSAHCI.

I think you will find that to be chipset dependent, not driver dependent.
I'm using a board with the c602 chipset and iaStorA driver and any drive plugged into a USB or eSATA port activates the "Safe To Remove" icon.
 

jkauff

Senior member
Oct 4, 2012
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Open the "IDE ATA/ATAPI Controllers" section of the Device Manager and look for the listed SATA AHCI Controller.
If there is a "Standard SATA AHCI Controller", you can be sure, that the generic MS AHCI driver named STORAHCI.SYS is managing this Controller.
After having installed any Intel AHCI driver named IASTOR.SYS, you will see an Intel SATA AHCI Controller.
You could also have both. I do, because my motherboard has an ASMedia SATA controller in addition to the Intel one.
 

BonzaiDuck

Lifer
Jun 30, 2004
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I think you will find that to be chipset dependent, not driver dependent.
I'm using a board with the c602 chipset and iaStorA driver and any drive plugged into a USB or eSATA port activates the "Safe To Remove" icon.

Well, that's a twist I didn't anticipate. Somewhere else I'd read that IASTOR might not "contain all features" available through MSAHCI, without mention of the one I noted. Howsoever I may have understood what I read, the "difference" would ultimately depend on the chipset as you say, since I have no reason to think you're spinning stories about your Xeon board.