Switch SSD to an onboard-devices eSata port just to use AHCI?


Sep 25, 2009

I just got myself a Crucial M2 256GB SSD.

It is currently installed on a rather old MoBo: Asus P5KC, in one of its 4 main SATA 3Gb/s ports, along with 2 other HDDs.

The problem is, in bios, my mobo doesn't allow any other options than:
Sata configuration [Enhanced]
Configure Sata as [IDE]
for those 4 Sata ports.

However, if I connect the SSD to the so called eSata port, which is somewhere else on the mobo, I can then in bios go to "onboard devices" and configure that eSata to IDE or AHCI.

I don't know much about what eSata means, and I've even heard that AHCI can somehow be bad for SSDs. But since most say SSD ports should be set to AHCI mode, I figured I should ask, if it's a good idea to move this primary SSD to the eSata port.

Thanks for any insight!

P5KC specs here, in case you need: http://www.asus.com/Motherboards/Intel_Socket_775/P5KC/#specifications

PS: I know that I'm not getting the full speed of my SSD due to my lack of Sata 6.0 Gb ports. I'm fine with that, for now.


Sep 13, 2010
AHCI is not bad for SSDs, it just allows some features like native command queuing and hot swapping, which is one reason that it is important for use on eSATA connections.

It really depends on whether your motherboard supports eSATA boot drives, as you can do it on Windows XP, Vista or 7.

You would need the eSATA driver during your Windows install if you decide to try it.

Personally, I would probably just use a SATA 3Gbps internal connector and IDE mode, unless you can get a clear yes answer to whether your board will support an OS installation and booting from eSATA.


Jan 20, 2011
Page 4-14 of your motherboard manual indicates that you should see an option for AHCI as well as IDE when you set your SATA Configuration to Enhanced.

Disconnect all drives from your motherboard and clear your CMOS (page 2-26).

Connect your SSD to port SATA1.
Set your SATA Configuration to Enhanced.
See if you now have an option to enable AHCI mode.
If so, set AHCI mode, save your BIOS settings, shut down pc and then connect your remaining drives to ports SATA3 & SATA4.


Feb 26, 2010
Sorry, Derek jumped in front of me, same info:

No, no, no: ACHI good!

But for your set up, set the SATA ports to Enhanced, then ACHI! And install the SSD to them.

Stay away from eSATA, you won't get the speeds of the internal ports, even in ACHI. Plus, "eSATA" stands for "external SATA", which the plug for is one the back of the motherboard I/O panel, and you'd need a power source, too. It'd get way to complicated.

And I was gonna say you dropped a bundle on an SSD that may not work in your system, but I see that Cruical 256Gb are less than $300.00. I would have said you shoulda upgraded your mobo & CPU, but that would be around $400.00. Plus RAM for $50.00. Nevermind.


Sep 25, 2009
Thanks for your replies.

Apparently the P5KC rom doesn't actually have the AHCI option enabled in bios, despite of what the manual states. (it seems that it used to, in older versions, but not in v1203, which is the latest) Funny how it gives you the option to choose between [IDE] and nothing else.

I've cleared the CMOS, removed all sata drives, and I can confirm that there's no other option than IDE.

However, after some digging I've found this thread: http://www.bios-mods.com/forum/Thread-solved-p5kc-bios-need-ahci?page=2
This guy made a custom rom for v1203, with the AHCI option available, and it seems to do the trick. No complaints.

So here's what I'm gonna do:
- enable the AHCI driver in windows because otherwise windows might not boot http://support.microsoft.com/kb/922976
- flash the bios with the rom provided on those forums.

Foscooter, you're right about the prices, and the thing is, even if I had upgraded my mobo & cpu & ram, I would have still needed an SSD. The HDD is bar none the hugest bottleneck in most systems. I have to say, things are 10x less frustrating since I bought it.

Done and done. :D
Flashed bios using Asus ez flash 2 and an usb with the .rom file.
Checked to see if AHCI option now shows in BIOS. It does.
Booted into Windows to enable AHCI using that .msi wizard.
Shut down, clear CMOS.
Enabled AHCI in bios and re entered my settings.
Booted to windows, windows recognized all my (as of now) AHCI sata devices and installed them.
Restarted due to being prompted by windows.


Jan 15, 2013
Hello. I know its an old topic,but i have the same problem.
I have this mobo,and recently a bought a SSD,Kingston HyperX 120 gb,and conected to that internal eSata (near grafic card slot).I enable the AHCI mode,and it seems everything is OK.TRIMM enable,AHCI enable,sistem stable,except... read/write speeds.I only get about 135 mb/s. I stay with the 0809(i think is this number) BOIS.
I already had found other topics were is metioned this tweaked BIOS,but i have a little afraid to put it and something goes wrong. Anyone have some feedback about this issue?
(sorry about my english,im portuguese)


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