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I am trying to install ubuntu next to windows. Encountering a problem with Intel RST and Ubuntu not being compatible with my NVMe SSD disk, I came across this post: Workaround to Install Ubuntu 20.04 with Intel RST systems The reply to that question suggests a way to fix the problem and install ubuntu without a problem. Then, there is a comment that indicates that for NVMe SSDs this fix might not work, but there are plenty of other comments that state that switching their mode to AHCI it works with their NVMe SSDs, without problems. In yet another article, however, I read that switching to AHCI might severly impair the performance of the SSDs in terms of read / write speed:

"Compared with AHCI, NVME protocol enables SSD to have better read-write performance, 
lower latency, higher IOPS (input/output operations per second), and lower consumption. 
An NVMe SSD’s speed reaches up to 3500MB while the speed of other SSDs is from 200MB/s to 550 MB/s."

200-550MB/s is still quite "fast". It might be that fast that users who switched their NVMe's to AHCI did not actually notice the degradation of R/W speed. Can anyone confirm that indeed their R/W speed dropped when switching to AHCI? If you did this to install ubuntu next to windows, did you encounter any problems related to the R/W speed? Also, as the post linked above is from two years ago, might there be a better solution for this problem as of now?

EDIT: I have two PCs on which I'd like to install Ubuntu in parallel:

  1. Dell XPS 15 9500, Bios Version: Dell, Inc. 1.12.0 08/12/2021, SMBIOS version: 3.2, with a single drive: PC SN730 NVMe SSD (1024GB)
  2. MIFCOM custom-configured Desktop: Intel i9, Bios Version: American Megatrends International, LLC 5.24 28/10/2021, SMBIOS version: 3.4

So far, I only tried installing Ubuntu in parallel on the Dell XPS.

Thanks!

JZ

user101893
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  • Do you have both a hard drive and an NVMe drive? The AHCI setting is really only for the hard drive. Linux uses a NVMe driver since about 2012. https://en.wikipedia.org/wiki/NVM_Express#Comparison_with_AHCI There was a recent announcement of the first hard drive using the NVMe interface although drive speed not really faster – oldfred Jun 02 '22 at 19:11
  • Hello, so, this means that the distribution of Ubuntu that I downloaded might really just be the wrong one for AHCI drives. Or do I have to prepare the ubuntu usb stick differently? I used rufus to deploy the image, with the default settings (partition scheme: MBR, target system: bios or uefi, but there is also: partition scheme: GPT, target system: UEFI without CSM). Do you think this might be the cause? If ubuntu can use NVMe, there must be a way to install it without changing to AHCI, that's what you are suggesting, right? – user101893 Jun 03 '22 at 18:35
  • Always have changed to AHCI, do not know if only NVMe if then it works. You should be booting in UEFI mode as almost all systems since 2012 are UEFI hardware. And Microsoft has required vendors to install in UEFI/gpt mode since 2012. Often systems need UEFI & NVMe firmware updates. – oldfred Jun 03 '22 at 19:02

2 Answers2

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So, what I did following the comments was:

  • creating a 100GB unallocated partition in Windows
  • upgrading my BIOs. 1.14.0 (the newest available for my XPS)

I then tried to install Ubuntu, still getting the "turn off intel rst" error. As a consequence, I did the switch from RAID to AHCI following this trick (Workaround to Install Ubuntu 20.04 with Intel RST systems). In the end, I now don't mind using AHCI mode, although it might come with speed decrease (which I did not determine, yet).

So overall, it seems that on some systems, if you're lucky (or not running intel rst), you can install ubuntu right ahead, even on NVMe (following the comment by sudodus), and on others you have to do the switch to AHCI like I did. My problem is resolved for now and I am writing this post from Ubuntu :P.

user101893
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If Ubuntu 22.04 LTS works for you, there might be a more convenient choice, because it can manage the Intel RST.

In a Dell Latitude 3520 Windows is installed with RST, and I could install Ubuntu 22.04 LTS alongside it without changing any setting in the UEFI/BIOS system. In a BIOS menu it is described as 'RAID on' with VMD controller which can be managed by Linux kernel VMD driver (available in 22.04). (I updated the BIOS while running Windows. It is now [Dell BIOS version] 1.17.4)

So I think it might be possible for you too, and worthwhile to test.

sudodus
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  • Thanks for the reply! My bios also shows the RAID on option. I did not update my BIOS or check whether there might be a newer version. So, you think, if I upgrade the BIOS, it could work? I added the specifications of my PCs in my main post. – user101893 Jun 03 '22 at 18:36
  • Also, i just read here (https://medium.com/linuxforeveryone/how-to-install-ubuntu-20-04-and-dual-boot-alongside-windows-10-323a85271a73) that it might be necessary to shrink an existing partition to set up a new one from windows, before proceeding to install ubuntu, which I did not do. Maybe, this is what caused the conflict when trying to parallel install? Did you set up a separate partition before installing on your NVMe system? – user101893 Jun 03 '22 at 18:42
  • You can try, and if it does not work, you can upgrade the BIOS from Windows. But I think it will work, because it works in my computer and our computers are fairly similar. - And yes, I let Windows shrink its main partition, and left 'unallocated drive space'. Then booted into the Ubuntu live drive (USB pendrive) and used gparted to create an ext4 partition where to install Ubuntu. But I think Ubuntu's installer can find and use the unallocated drive space automatically too. – sudodus Jun 03 '22 at 18:43