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Which is the best setting in BIOS for SATA operation mode for a laptop to connect SATA III based fast SSD drive, and why?

  • ATA
  • AHCI
  • RAID On (Intel Rapid Storage)

There will be no RAID set in system (laptop with 1 drive slot only). I've read that "RAID On" enables AHCI anyways but would prefer some confirmation that one is better then the other.

For the sake of example the laptop I'm talking about is a Dell Latitude E6420 with an Intel Core i7-2720QM, 8 GB of RAM and an aftermarket SSD, an OCZ VTX3MI-25SAT3-240G Vertex 3 MAX, which will replace other standard drive that's inside.

But this questions is asked as general for future reference.

Some reference: How to configure the BIOS for RAID or AHCI on an Intel® motherboard

If you are using a SATA hard drive, set your BIOS to RAID mode. RAID mode provides the greatest overall flexibility and upgradeability because it allows your system to be RAID ready and enable AHCI.

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up vote 2 down vote accepted

Advanced Host Controler Interface (AHCI) is the best option if you have only one Hard Disk (or Solid State Disk). It provides the best interface to SSD-Operational System transfer rates for reading and writting. More information about AHCI you can find here.

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According to Intel link Raid On enables AHCI. Is it still better to use AHCI anyway? – MadBoy Jul 19 '11 at 17:00
If you have only one Hard Drive I would recommend you to use AHCI, with RAID mode your BIOS would try to find for another Disk expending time on boot. – Diogo Jul 19 '11 at 17:11
@MadBoy: RAID needs AHCI, but if you don't need RAID why would you enable it? Besides, it's not even real (hardware) RAID, you still need some software for it. – Cristian Ciupitu Jul 19 '11 at 17:19
All Dell laptops that I work with have default Raid mode. I guess one can safely assume that laptops hold usually 1 drive. Shouldn't it be default for laptops to AHCI then? I'm asking this because maybe there's more in the RAID option then simply raid. – MadBoy Jul 19 '11 at 19:30
I downvoted because both the "ACHI" and "RAID On" options enable AHCI on the E6420. Selecting "RAID On" enables Intel-specific RST enhancements. – Michael Steele Feb 27 '13 at 23:24

Note that under Windows, you have to install different disk controller drivers to match different SATA modes and I suspect some RAID mode drivers may be better/worse than AHCI drivers. (On my AMD SB710 chipset, the RAID driver seems to be slower.) Or maybe computer vendors recommend you to use RAID mode so you won't have reinstall to drivers if you switch to RAID (through eSATA or second drive bay?).

If you use Windows and is not afraid of blue screens, you can switch between these two modes and use disk benchmark software to determine which mode is more efficient. Make sure you change your driver first and then change the mode in BIOS.

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Also make sure you backup your files prior to attempting this since you may need to reinstall windows if blue screens come up on boot. – mtone Feb 28 '13 at 2:22

Adding my experience for anyone searching. Dell E6520, fresh Windows 10 install on new single SSD. Windows 10 would only start with the install DVD. Changed BIOS from RAID to AHCI then got the blue inaccessible device error. Performed a reset from the install DVD and problem is fixed.

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I just installed a Samsung PM853T 960GB SSD as the primary drive in my E6520. The SATA operation mode was set to the default RAID selection. I cloned the original 1TB HDD with Acronis TIH's clone utility. The initial boot failed but the second boot and all subsequent boots have been flawless both for the first partition (Windows 10 Pro) and second (Windows 7 Pro). The PM853T is a data center oriented drive. I am getting 540/430 MBs performance, which is what the Samsung specs call for on this model.

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