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Raid vs. AHCI

New Dell XPS 8930 computer, Main drive/operating system is on PCIe, but all my files reside on a Samsung SSD. While poking around in BIOS concerning an odd problem, I see "SATA Operation" is set to "Raid On", rather than AHCI. There is no Raid set, of course, each drive runs separately. However, just out of curiosity, on the Samsung SSD, when I right clicked on "Format" the notification said "drive was being used" (how?)
Going back to BIOS, when I went to switch from RAID to ACHI, I get the dire warning that my computer may be unbootable, etc.; are you sure...
I didn't change anything, but would anything bad happen if I switched it to ACHI?

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All Answers

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At worst the machine will lose what's on that drive.

In reply to: Raid vs. AHCI

Everyone has a full backup in case that happens. I don't see why anyone would tinker with this.

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Of course!

In reply to: At worst the machine will lose what's on that drive.

Yes, I'm beyond belief with back-ups.
I didn't get into what the original problem is, but what happened was - after getting everything set up and programs installed, I went to create a system image on an external drive. When it asked "which drive(s)", C was pre-checked of course, but without thinking, I checked D also, as there was plenty of space. When that was done I went to burn a Repair Disk. Upon clicking, it immediately said "Can't create a repair disk" Unspecified error - 0x80004005. I couldn't find anything helpful, or related to the problem. Meanwhile, I found that I could not edit a photo on my drive D, but if I copied it to my 3rd drive ("E" back-up for D) I was fine. That got me thinking about how I included D in the back-up...
I disconnected D and E, formatted my external drive, and re-did the System Image.
I will now disconnect both D and E, and change "Raid - On" to ACHI.

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Well, that didn't work

In reply to: Of course!

It wouldn't boot to operating system without drive D connected. I changed it back to "Raid-On".
I don't know why this happened. Somehow my secondary drive D is now part of RAID.
I usually don't have a problem wiping a HD and re-installing from scratch, but not so soon after all the time & effort I've put into this for the past couple of weeks.
Besides, I pulled out my 2011 model Dell Latitude, running Windows 10 now, and burned my Repair Disk.

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Story time.

In reply to: Well, that didn't work

I can't guess who or why they set this machine up this way. But Dell tends to set the BIOS to a one size fits all so RAID may be the config that works for every configuration they sell so that's the default. I do see folk write they change the BIOS drive setting and blow up the OS. Here's how I think they do that.

1. Change the BIOS setting.
2. The machine doesn't boot.
(Here there be dragons)
3. They boot any number of boot repair tools and trash the drive contents.
4. They finally put the drive back as it was when it worked.
5. It still doesn't boot and all boot repairs fail.
6. They post widely on the Internet.
(some do the following.)
7. Post widely on the Internet what a trash company Microsoft is for allowing them to trash their PC with a "simple change."

I won't dis them here but hey, hand them a hammer, what's the worst that could happen?

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Del or MS?

In reply to: Story time.

It worked fine when I first started it up. I didn't add the second drive where my personnel files would go for a day or two. I only noticed a problem after I created the System Image and included drive D. I don't see how this would have a "backward effect" but I have no idea what else could have done it.
I'll re-do it one of these days. I guess I can't use the System Image I created, as that would just put me back in the same boat!

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So Dell or Microsoft?

In reply to: Del or MS?

Microsoft makes their Surface PCs so the default would be likely a Dell choice. The System image should include drive D as it's often the recovery drive and more.

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When do-over day comes

In reply to: So Dell or Microsoft?

I'll just have the on board PCIe (as originally) but I can then change BIOS from RAID to AHCI? Then if I create a System Image I do it before attaching any other drive. Does that sound like a plan?
Buy the way, I can't think of any benefit from complaining to Dell or MS. No matter what the outcome, I still have to do all work myself.

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I'm missing something.

In reply to: When do-over day comes

Since it's working, why must this be changed?

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Good question

In reply to: I'm missing something.

Just simply because it's not how I want my computer set up. I never thought RAID was a good idea and I don't need it.
The operating system was on one single drive. I added a second drive for my personnel files, and Windows system files started to appear on it (I noticed last night it predated the creation of the System Image).
I have a feeling it's a complication that will be a problem someday. Not to mention that I'm cursed with being a perfectionist Happy . To get it right I really don't mind re-installing an operating system and programs, with the exception of setting up Outlook 2016 and the transfer of my 15 years of saved emails. Also, I have a few other computers to use if needed.

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I didn't cover a thing.

In reply to: Good question

The drives may be attached to some Dell RAID controller even if not in a RAID configuration. I can't guess your PC's exact configuration but changing this is at this point either cosmetic which is to be put out of our minds or will end up with a non-working machine because the Dell design uses a RAID chip rather than a SATA chipset and Dell did that because they have standard designs and models in that line that offer full on RAID drive systems.

In short, I would not bother changing this.

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I'll talk to Dell about it

In reply to: I didn't cover a thing.

With slots for 3 hard drives besides the PCIe, they couldn't all be stuck to a RAID system. It doesn't make sense the way it is; if I wanted to replace my secondary drive the day after I connected it for one of larger capacity, I couldn't do it now?
I'll ask Dell what the options are. If I have no satisfactory options, I may ask to return it! I was happy with my 2011 XPS 8300 w/W-7.
Thanks for you info.

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I was unclear.

In reply to: I'll talk to Dell about it

Just because the drives are connected to a RAID Controller or Chipset does not mean they are in a RAID configuration. As to the larger drive, until we know more I can't write there is or is not a future problem.

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In reply to: I was unclear.

No, it's apparently not configured for RAID. What happened is, when I first connected my Samsung SSD drive, it showed as drive D. Yes, drive D is "System Reserved" partition, so both were assigned drive D! - for some reason.
After shutting down, unplugging the computer, then disconnecting my extra drives, after restart "System Reserved (D:)" appeared. Reconnecting my SSD now is "Drive E". I've found unplugging will sometimes straighten out mysteriously changed drive letters. Like yesterday when for some reason an extra "CD drive (H:)" appeared!
So all is well now. Thanks- also for making me step back and give it more thought.

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