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onesnark
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XPS 8900, BIOS setting, Raid vs AHCI

I was prowling BIOS settings to resolve a different problem. I noticed that the BIOS is set to run SATA drives in RAID, rather than AHCI. Which should I use?  I have a single HDD in the system now. Probably will go to a SSD (Boot) and HDD (Data) in the future (next week). 

Windows 10
BIOS 2.0.1 (not upgrading!)
No plans to use Raid 

I saw this thread: https://www.dell.com/community/Desktops-General/AHCI-disabled-on-XPS-8900-desktop/td-p/4673037/page/... which leads me to believe RAID is the "factory default", and that I will have some small, manageable hoops to run through to make the switch. 

Thoughts?

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18 Replies
RoHe
6 Thallium

Re: XPS8900: Bios setting: Raid vs AHCI

If you have a small (32-GB) SSD installed that's used as a cache by Windows, you have to use RAID.

If you install an SSD as the boot drive, you can set BIOS to AHCI if you're doing a clean install, in which case the 32-GB SSD can be removed since Windows won't need it.

Ron

   Forum Member since 2004
   I am not a Dell employee

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onesnark
1 Nickel

Re: XPS8900: Bios setting: Raid vs AHCI

I have heard reference to the 32gb SSD before.

I take it that was a standard option on these boxes at some point? In any event. . . I don't have one. It would show up in "disk Management", or on the BIOS SATA screen right? And I would SEE it in a drive slot if I opened up the case?

Yeah -  Plan to do a clean install, with the current HDD remaining as a (likely way underutilized) data drive, and the SSD for the O/S and programs.   Don't need Raid for that.

 

Thanks!

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RoHe
6 Thallium

Re: XPS8900: Bios setting: Raid vs AHCI

If you have it, the SSD cache probably won't show up in Disk Management because it's treated as part of the HDD.

It would be plugged into an M.2 slot on the motherboard (#16 on page 16, here). It's not in a standard drive bay and not directly connected to one of the SATA ports on the motherboard.

If BIOS is set to RAID, I would assume you have that SSD cache. Otherwise, I don't think Windows would boot because it would be looking for another drive in the RAID array that doesn't exist.

Go to the support site and put in your Service Tag. On the next screen, click the System Config button and then on the tab for original config. Look on that list to see if an M.2 SSD is listed.

And if you have that SSD, you probably will want to remove it before installing Windows on the new SSD, with BIOS set to AHCI. You could eventually reinstall it and use it for extra, but small, storage.

 

Ron

   Forum Member since 2004
   I am not a Dell employee

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onesnark
1 Nickel

Re: XPS8900: Bios setting: Raid vs AHCI

** EDIT: Because the original version was rushed. **

 

Huh. . .that slot doesn't LOOK like a M.2 connector. I see the M.2 drives offered currently as options for the 8900 by Dell; they don't look like they will fit this slot.

 Regardless. . . the slot you suggested to check is empty.  I have also seen implications to being able to install a SSD in #26. On my motherboard, I have a WIFI thing (or something with a MAC address)  in # 26.

I did plug the service tag into the Dell Website to check the "as built" configuration. A M.2 SSD is not listed - - -> So I expect that I never had one. If it was an "up charge" in the original build, I would not have selected it; as I knew my real plan was to replace the HDD and put in a clean Win10 Load ASAP.  My plan now is to just slap in a SATA 2.5" SSD into a HDD bay using a 3.5" adaptor and an appropriate connector to the MB (and to the power supply). The current HD will become a data drive in the system.

(A new power switch is also on the list; per our conversation in the other thread) (What could go wrong!)

Looking at the original configuration. . . and what the machine is now. . . amazing to see.  Changed the Video Card and HDD upon purchase. Changed the RAM mid last year (8GB to 32GB).  Now just changed the Power Supply. Still running the original fans, CPU, and motherboard. OH. . and DVD.

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546insp
3 Argentium

Re: XPS8900: Bios setting: Raid vs AHCI

My 8920 won't boot ahci no matter what I do.

Dell XPS 8920 silver edition
7th gen i7 Intel CPU
Samsung 850 evo SSD for boot
Added front fan
16gb of memory
AMD video/graphic card
I buy a new Dell every 4 years for the last 25 years

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RoHe
6 Thallium

Re: XPS8900: Bios setting: Raid vs AHCI


@546insp wrote:

My 8920 won't boot ahci no matter what I do.


It's not helpful to  jump into the middle of someone else's thread with a problem on an entirely different PC model...

Ron

   Forum Member since 2004
   I am not a Dell employee

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546insp
3 Argentium

Re: XPS8900: Bios setting: Raid vs AHCI

The two are closely related and it's not helpful to get on my case about nothing.

Dell XPS 8920 silver edition
7th gen i7 Intel CPU
Samsung 850 evo SSD for boot
Added front fan
16gb of memory
AMD video/graphic card
I buy a new Dell every 4 years for the last 25 years

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BobVu
1 Copper

Re: XPS8900: Bios setting: Raid vs AHCI

I have bought Dell's laptops and PCs since 2007. From GX270, GX620, Optiplex 745, 755, XPS 8100, 8300, 8500, 8700 and 8900. In my opinion, the RAID option is for professional and server PCs, so it is stupid to make the BIOS default in RAID mode. This causes a lot of problem for majority of buyers like you and me. The XPS line is very good up to XPS 8700. From 8900 and up there are design problems and motherboard quality from China, so I see a lot of issues that even Dell folks do not know what's going on.

I had an 8900 weird issue with the BIOS keeps going back to default RAID mode and "Time-of-day not set". I'm a retired electronics engineer and very good at troubleshooting both H/W and S/W of aircraft controllers, now also at Dell's laptops and PCs. I replace with a new coin battery, bend up the GND tab of the coin battery, extend the + tab, re-solder their GND and + post on the underside of motherboard with the same result. So it is not a H/W coin battery issue that resets the BIOS to default condition. I was so frustrated and think it got to be S/W, so I change BIOS from the latest 2.4 go back to 2.1.8, 2.1.3, 2.1.1, 2.2.1, 2.3.... same result.

Finally, I found out the Power cord have to be removed or switched off on the power strip after a shutdown, then it solved it.  So, I think a  staff of young engineers and talented in Facebook revised the 8700 motherboard and new S/W for the XPS 8900 and up, results in a lot of weird and stupid problems.

I hate iphones and smart phones because they make young people dumber, not smarter, create a lot of weird and unnecessary apps...... So, try every unimaginable ways to solve your XPS 8900 and up because the H/W and S/W design was seriously compromised by the above staff of young engineers and talented in Facebook .

Good luck to Dell buyers

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Techgee
2 Iron

Re: XPS8900: Bios setting: Raid vs AHCI


@RoHe wrote:

@546insp wrote:

My 8920 won't boot ahci no matter what I do.


It's not helpful to  jump into the middle of someone else's thread with a problem on an entirely different PC model...


...especially when it seems to be misinformation and the operator.  AHCI mode works and boots just fine on the Dell XPS 8920, even with a NVMe M.2 SSD.  Of course, your BIOS needs to be up-to-date (or at least v1.10, which came out around October 2017).


@BobVu wrote:

... it is stupid to make the BIOS default in RAID mode. This causes a lot of problem for majority of buyers like you and me.


Yea, I make it a point to switch from RAID to AHCI every time I buy a new machine.  RAID is just pointless to the average person.

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