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Best Hard Drive Options in BIOS

Last response: in Systems
August 5, 2010 4:59:14 AM

Hi All,

I'm currently putting together my first build. I'm a bit undecided as to what setting to apply to the hard drive. I would like to have the option to add a second hard drive as a backup later on. In BIOS, should I use IDE, RAID or AHCI? And could I just use an external hard drive as a backup or would an internal be better?

This is my first time using SATA. In the past, when I used two hard drives, it was IDE and in a master/slave configuration and the cable connected the two. I have a bare drive with no jumpers, so I'm a bit confused.

August 5, 2010 5:33:50 AM

If you are using Vista or anything after it, ACHI would be great. IDE mode is for backward compatibility with older OS's, and RAID is for, well, RAID arrays.
August 5, 2010 6:41:44 AM

I'm using Windows 7.

I wanted to know what would be better because I read that after Win 7 is installed, the hard drive setting couldn't be changed. I don't have an extra hard drive now, but I might add one later on and I just wanted the best option. This is my first build and I don't want to mess anything up.
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August 5, 2010 8:17:56 AM

Also, would RAID be better if I wanted to use just 2 drives? Can AHCI be used with 2 drives?

I really need some help and I'm stuck on this.
August 5, 2010 3:02:30 PM

Opal said:
Also, would RAID be better if I wanted to use just 2 drives? Can AHCI be used with 2 drives?

I really need some help and I'm stuck on this.

Without having any specs (Mobo, make and model of HDD's) to go by, I'd suggest you use AHCI. It allows for advanced software use (command queing, etc). Setting up a RAID array require two or more drives but can be problematic if you don't have drives specifically designed for use in a RAID environment. It has to do with error recovery (known as TLER), which can cause a drive to drop out of an array under certain conditions. But, (knock on wood), I've had a RAID array going on two older WD drives that aren't certified for RAID but have worked just fine. Many people recommend that if you're going to have a RAID array on your system, that you NOT use it for the OS.
August 5, 2010 3:23:58 PM

Yes you can have more the 1 drive under AHCI, AHCI is just a interface you can have as many drives are you have ports, each drive will be available in windows. you can add drive at any point after you install Windows.

AHCI Wiki:

AHCI is you best option with 1 drive and wanting to add more later. To create a RAID you must have 2 drives.You will have to reinstall Windows if you add the second drive and want to use a RAID array.

a b B Homebuilt system
August 5, 2010 4:01:47 PM

Echo: when using Win 7, set all SATA Port Modes to AHCI. You do NOT need to set IDE (which reduces the drive's abilities in a few places). You do NOT want RAID if you don't understand the various versions of it, their uses and weaknesses.

RAID requires more than one HDD unit. BUT you do NOT need RAID to use multiple drives as separate storage devices - normal operations can do that.

You are familiar with IDE, but not SATA. IDE can support up to 2 devices each port / cable, and so the devices need unique identifiers. The system was to use jumpers on pins to identify each as either a Master or a Slave of that one port. SATA uses only ONE device per port, so there are NO Master and Slave settings. Although some SATA units do have jumper pins on them, they are for different purposes entirely. As a general rule you should NOT change these - in a few cases setting them wrong can make your drive look dead!

Your first HDD should probably be attached to the first SATA port, probably labeled SATA_1. You'll probably have an optical drive, too, with SATA connections and it can hook up to the next one. (Technically, it is not supposed to matter which port you use.) If you add another SATA drive later, just plug it into a port not yet used.

On some mobos, there may be two slightly different groups of SATA ports. The first several are all controlled by the main mobo southbridge. Then there may be an additional group controlled by another mobo chip. For certain types of systems (like creating multi-disk RAID arrays) it can be important which group you connect a drive to. In some systems you MUST connect the drive you want to use as the boot device to the first group of ports controlled by the southbridge. But for most simple uses of additional HDD's, which port is not important.

In the old days of IDE systems, it was common that the boot device by default was the Master device on the Primary IDE port. Because of this people have fallen into a false habit of considering that device to be the "Master" of the entire machine, and all other drives to be "Slaves". NOT TRUE! "Master" and "Slave" are only different designators for two units that share one IDE port and cable. In the SATA world there is not such thing.

These days the question of which drive is the boot device is set up completely at the direction of the user by settings in the BIOS Setup screens. (There can even be more than one possible hard drive to boot from, each with their own OS's installed, but that's getting complicated.) All other drives are just non-bootable units able to handle any data.

In many cases the best Boot Priority Sequence to set is the optical drive comes first, then the HDD that you mount your OS on, and then no other option. That way if you place a bootable disk in the optical drive it can boot from there. But if you don't, the attempt to use that device will fail and immediately the machine will go to the second device (the HDD) and boot from it. (On my own machine, I have 3 devices in the sequence - my floppy drive is before the other two.)

For backup purposes you need to consider what is needed for reliable backup, which includes what are the dangers. Obviously you're protecting against data loss or corruption. But there are other issues also. The damage could come from an electrical spike or from malware, so having the backup device DISconnected from power and the computer can protect against that. You might have damage to the building where the computer is located, or a thief might steal your machine. That is why OFF-SITE backups are advised. For these kinds of reasons, an external HDD unit is best. You can make your backup and at least disconnect it from power AND the data interface cable. Ideally you carry it to an off-site storage place and only bring it back when needed. Very few people would consider a second INTERNAL HDD as a reliable way to do backups.
August 5, 2010 8:05:05 PM

Thanks, Paperdoc! You broke that down nicely! I'd googled so much last night (and early this morning) and had so much info in my head... :pt1cable: 

1haplo: Yeah, it would be nice if I listed the mobo, huh? Oops, lol! It's ASUS P6X58D.

Thanks again, guys. That really helped a lot!