BIOS set to AHCI, but software not recognising it?

tutuava

Member
Aug 28, 2011
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I'm trying to set up a Samsung 830 on a 6 year old Asus motherboard with Windows Vista. I have SATA set to AHCI in the BIOS, and Windows installed fine, but Samsung Magician tells me that it's not running with AHCI enabled. I checked the benchmark because it was very slow (like a hard drive) and indeed the random IO numbers were much too low (but sequential was fine). Is there something I can do to enable AHCI properly? Should I try to update the BIOS or is it a Windows setting?
 

tweakboy

Diamond Member
Jan 3, 2010
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www.hammiestudios.com
Set your BIOS to AHCI and then boot to windows and follow these instructions to get the msahci going in windows as well.

http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&ved=0CCEQFjAA&url=http%3A%2F%2Fforums.guru3d.com%2Fshowthread.php%3Ft%3D354428&ei=_dCVUJu4C-bmiwKdxYCYCg&usg=AFQjCNESe65gin13muDYNL-re2GlvjF0Mw&sig2=lIQ5ymmuC-Vb5vrIz0Ptug

It is a registry entry as you will see in instructions, and you will have AHCI enabled after rebooting. gl

regedit entry, Im not responsible for any casualties. jk everything will be ok. You can also just set mobo to default do the registry entry then reboot and change mobo to AHCI and boot smoothly into winblows,, it will be faster.. gl
 

taltamir

Lifer
Mar 21, 2004
13,576
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Tweakboy, at least read what a person has to say before you start giving advice. The OP does not need a guide on how to switch windows from IDE to AHCI without reinstalling. He says he already switched it to AHCI before installing windows.

@OP: Which port did you use to plug the HDD? A lot of mobos have 2 SATA controllers, so you could have turned on AHCI on the wrong one. (Ironically, if you did do that then you will need the guide tweakboy linked but that is out of sheer coincidence)

PS. If there is a bios update, use it.
 
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tutuava

Member
Aug 28, 2011
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Sorry for not getting back sooner.

Hmm didn't see any word in the BIOS about the ports having separate AHCI/IDE/RAID setups, I think there was only one place to change it but I will look for that again. I was pretty happy the motherboard even supported AHCI since it's old (an ASUS P5B I think)..

I don't have it here, but I'll get to toy with it this weekend. I'm confused about potentially needing to install the Intel AHCI driver mentioned in the other link, is that for older motherboards or older version Windows?
 

taltamir

Lifer
Mar 21, 2004
13,576
6
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What is your mobo make and model?

EDIT: I see ASUS P5B... can you confirm that is it?

Found the following info for the P5B:

Southbridge
- 4 x SATA 3.0 Gb/s ports
JMicron® JMB363 PATA and SATA controller
- 1 x UltraDMA 133/100/66 for up to 2 PATA devices
- 1 x Internal SATA 3.0 Gb/s port
- 1 x External SATA 3.0 Gb/s port (SATA On-the-Go)
- Support SATA RAID 0, 1 and JBOD (by 1x External SATA & 1x Internal SATA)
As you can see, 4 of your SATA ports come off of the intel southbridge while others come off of a Jmicron controller.
You must have turned AHCI on on the wrong controller. Note that if you just turn it on now, windows will fail to boot. You need to enable AHCI in windows itself before making the change in the mobo.

Also your intel southbridge SATA controller should be a good bit faster then the jmicron so you would benefit from booting windows off of it instead.
 
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tutuava

Member
Aug 28, 2011
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I'll have to look at it when I get a chance. The setting for AHCI in BIOS was buried deeply enough that I hardly found it, and there didn't seem to be more, but I'll take a look. Pretty sure on the motherboard model, but we'll see.

To enable AHCI in Windows Vista do I need to download the Intel AHCI driver and/or go change that stuff in the registry as per the link?
 

taltamir

Lifer
Mar 21, 2004
13,576
6
76
The link from tweakboy is actually for win7, I am not sure if its the exact same registry setting or if it is a little different.

To answer your question on which driver to use... both.
If you read the link carefully, it says so as well.

1. Change the settings in the registry as per link to enable MS AHCI driver.
2. Go into BIOS and enable AHCI.
3. After booting back into windows with AHCI enabled, install the latest intel driver (referred to as the "power driver" in the link).

Are you using 64bit or 32bit vista?

Also, if you do it wrong then windows will blue screen midway through booting up when you next turn it on. Simply go back into bios and return it to IDE mode and then windows will start working again. So its safe, you don't have to worry about messing up.
 
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blackened23

Diamond Member
Jul 26, 2011
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Sorry for not getting back sooner.

Hmm didn't see any word in the BIOS about the ports having separate AHCI/IDE/RAID setups, I think there was only one place to change it but I will look for that again. I was pretty happy the motherboard even supported AHCI since it's old (an ASUS P5B I think)..

I don't have it here, but I'll get to toy with it this weekend. I'm confused about potentially needing to install the Intel AHCI driver mentioned in the other link, is that for older motherboards or older version Windows?

6 year old motherboard? Thats like, C2Q era isn't it? You will likely need to run IDE. Motherboards that old usually don't support AHCI. Drivers won't do anything if your motherboard doesn't support it.
 

tweakboy

Diamond Member
Jan 3, 2010
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www.hammiestudios.com
There is a registry key that enables AHCI even if you install OS with IDE . Bios should be set, but software will take care I believe.

search google for "how to enable ahci in windows 7

It is registry key, you switch the 1 to 0 ,,,,,,,, reboot and your AHCI ,, it will install proper driver on bootup. enjoy! its first result in google. GL
 

blackened23

Diamond Member
Jul 26, 2011
8,548
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Tweakboy, what you're referring to is switching between AHCI and IDE on the fly - there is a registry hack which will let you do that. The hack allows you to use your existing windows installation without reinstalling. You cannot, to my knowledge, supersede the fact that a motherboard doesn't support AHCI.

If the motherboard doesn't support AHCI, you are out of luck. You must run IDE mode.
 

tutuava

Member
Aug 28, 2011
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I had a chance to work on it today and although it seems that I got everything set up it is still really slow in the random IO (by an order of magnitude according to Samsung Magician and it just feels like a hard drive speed too). It does say that it's running on AHCI now and I set it with the driver, BIOS, registry, everything.. can't really think of anything else I can do, this computer just seems cursed between this and a lot of other problems I got on it even though everything is freshly formatted and installed and updated.

But thank you everyone for helping out!
 

taltamir

Lifer
Mar 21, 2004
13,576
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76
Is the SSD plugged to the intel or the JMicron controller? It should be plugged to the intel
 

tutuava

Member
Aug 28, 2011
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I'm not sure actually, I looked at the motherboard and only saw 4 SATA ports grouped together. I tried putting it in another and although it was recognised it gave similar results. You think it would also affect random IO numbers and not just max transfer rates?
 

taltamir

Lifer
Mar 21, 2004
13,576
6
76
I believe so, if you could find your mobo's manual it should detail which ports go to which controller
 

bramke

Junior Member
Oct 18, 2012
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i have my bios set to ahci its windows 8 but software says this
is my pc running in ide? how can i change windows 8 pro to ahci?
 

taltamir

Lifer
Mar 21, 2004
13,576
6
76
You should undo all those tunes in the picture.
Superfetch should be enabled, it boosts performance.

Defragmentation should be enabled, it will only defrag your HDDs not SSDs and it does not launch a process on boot, only when its scheduled (which requires having an HDD)

Indexing should be enabled for faster searching. It has negligible effect on lifespand. It only had a negative effect on performance with first gen SSDs that were slower then HDDs in random performance. (SSDs went from 2 orders of magnitude slower than HDD to 2 orders of magnitude faster than HDD in random performance since than; total increase of 4 orders of magnitude)
 

taltamir

Lifer
Mar 21, 2004
13,576
6
76
i have 2 sata 3 ports
is it possible one port doesn't support ahci of those 2?

According to the info I found and posted earlier, all your ports are SATA 3 gbps (which is SATA v2 actually; SATA v3 is 6 gbps)
 
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