Helios 500 (mine: Predator PH517-51): replacing hdd with ssd, installing OS on that ssd, and taking the 2x M.2 out of Raid and into AHCI. Giving you two separately accessible M.2 drives (e.g. D and E) instead of one.
Okay, I am sharing this info because A. it was hard to find it in one piece elsewhere, and B. I first approached this all wrong and ended up paying for it (in time, lots of it).
If you don't want to replace the hdd with an ssd, the below is still relevant, if you want to get rid of the Raid 0 (disk striping).
DISCLAIMER: any actions you take, are completely at your own risk, and completely outside my responsibility.
Notes on replacing the hdd with an ssd: the (hdd) disk is squeezed into a rubber ring, I presume to tackle vibration. I found no way to get the hdd out of this rubber, without getting to the bottom side of it (which takes more 'opening-up work'), and then pushing the hdd out from that side, which then was easy. Videos on Helios 500 maintenance are found on YouTube (but didn't yet show hdd replacement).
Since I work with NLE (video editing) and live streaming/recording programs that really benefit from fast cacheing drives, I wanted to use the 2 NVMe's (M.2) for that, and have the OS on an ssd. The ssd in my case is an EVO 860, write 300 MB/sec, read 500. For my work, that is fast enough, the OS drive does not need to be faster than that. The NVMe's now (AHCI, so non-RAID) give me around 850 MB/sec for read and write, so they are clearly faster than the ssd. I have no personal info on the NVMe's speed while in Raid 0 (probably the review sites like the excellent notebookcheck.net do), but un-Raided they approach 1 GB/sec (850 MB) which is very fast, and much faster than the ssd.
So why was my journey to get the OS on the ssd and the NVMe's out of raid so painfull? No doubt, partly because of my own ignorance and stupidity. Secondly, Acer gives no clear info on this AT ALL for the Helios 500. When you power it on for the first time, it installs Win10 on the Raided NVMe's, same for the boot (EFI) partition, and there the trouble begins.
No doubt there are alternative ways to what I will describe below (please add them in comments or a new thread; thanks!), but the one I tried initially (cloning the OS to the freshly installed SSD) is not the one to go. Since cloning the OS to the ssd leaves the boot partition (EFI) on the Raided NVMe's, disabling Raid (enabling Ahci in the BIOS /F2 during boot) will make the system lose access to the boot partition, giving you an unbootable 3.000 Euro laptop.
And no (unfortunately!), when first installing Windows, this laptop does NOT ask you, on which drive you want to install !!!
And yes, I tried about 5 ways / tools of moving/cloning/copying/transferring the EFI boot partition to the ssd, but none worked. The laptop kept wanting the boot partition on the Raided drives, and accepted nothing else.
So, i hindsight, the only way that worked for me was:
let Windows be installed 'as is', meaning on the Raided NVMe's;
replace hdd with ssd as described above and verify that ssd is working / writeable. Format it as NTFS, GPT.
grab a usb thumb drive of at least 8 GB that is empty or may be formatted (all existing data will be lost)
Google "create installation media for windows 10" and follow the steps to transform the usb drive into a Windows installer drive
(probably this can also be done on a different PC with genuine Win10 on it; in that case, you won't need to install Windows from the Helios first; but I'm not sure if you might run into activation trouble later on, on the Helios)
Download the Wifi/Wlan drivers for your laptop from the Acer site if you don't have wired Internet ! The latest MS Win10 installer does NOT include drivers (yet) for the wifi card in the Helios!
Put these drivers on the / a usb drive.
Reboot the laptop, hit F2 when it restarts to access the Bios, and take the laptop out of Raid by choosing AHCI instead of Intel RST (Rapid Storage Technology) / RST Premium with Optane (the / my laptop does not come with Optane memory anyway).
NB ! when you continue, you will LOSE the Acer Windows installer/recovery that is on the NVMe's. For me, it's not a big deal since I don't care for the Acer bloatware and Microsoft lets me make my own (usb) installer (i.e. Step 3), but hey, you may feel different. There may be ways to salvage/clone this Acer recovery partition, but I spent enough time on this whole ordeal already, so I didn't look into that.
Save bios, exit, the system reboots and (don't be alarmed) will tell you No bootable device found (the only bootable devices were the Raided NVMe's, that you just un-Raided).
Put the usb drive with the Win10 installer in.
Power off and power on the laptop, hit F2 when it starts, to access the Bios. Make sure the Boot order has Usb in first place. (Might also work when in 2nd place, but just in case.)
Also, check if Touchpad mode is in Basic (only after Windows install, put it on Advanced, again via the Bios). If you use a mouse, you can ignore this check.
Save bios, exit, the system reboots.
Since you are now booting from the usb drive, the installation of Windows 10 should start.
This time, you CAN choose which drive (in my case: the ssd) to install it on, since you are now using the generic Microsoft installer, and not the image that Acer has put on the system, with pre-defined Acer settings. NB: this also means, you will not install Acer software (bloatware). Later on, via the Acer website, you can download and install Predator Sense, which seems usefull. All 'Acer' drivers that are not installed right away, are installed when doing Windows Update (but see Step 4 about Wifi drivers). No need to download them from the Acer website. NB 2: creating installation media (as described under 3) has the advantage that this package may already include major Windows updates (like the April/Spring 2018 one), which may be absent in the Acer-image that the laptop comes with. Of course, they can always be installed anyway, but it seems more elegant/robust if they are in the original installation package as provided by Microsoft).
After installation, use Disk Manager to check if you have indeed 3 drives, with Windows on the ssd (C:) and probably with the other 2 (NVMe) drives unformatted.
Install Wifi drivers (see step 4.) in case you are not on wired Internet.
Delete existing partitions on the NVMe's, if any. You may need to open a Command prompt (or PowerShell) and use Diskpart for that. Google 'Diskpart' and learn how to select volumes and delete partitions.
Format the two NVMe's (NTFS) so that one NVMe becomes D and the other E and they both have only one partition, that utilizes all the space of the disk.
Run Windows Update (several times, until it says Up to date), which will install all other drivers & updates for you.
If you are worried about disk performance, download the free Blackmagic Design Desktop Video suite, which includes Disk Speed Test. Be aware that when testing sustained (!) writing, performance for drives gets really tested, and is usually slower than advertised. As mentioned above, I get between 800 - 900 MB/sec on the NVMe's when they are tested separately (not sure how to test them simultaneously, and not sure if that would lower performance).
As mentioned: via the Acer website, you can download and install Predator Sense, which seems usefull. It configures the RGB lighting, overclocking, and fans/cooling.
After installation, you will see that on the OS-drive, there is a recovery partition.
I am not sure what it contains and how to use it.
I would advise anyone to continuously make full backups both locally (e.g. with the free EaseUS ToDo Backup) and in the cloud (e.g. Carbonite), as well as to make Windows restore points manually every so often.
10. Put Touchpad in Advanced mode via the Bios (enables things like 2-finger scrolling).
What were the benefits again, of this whole circus? Well ... I wanted my OS on an ssd. Plus, I wanted the fastest (i.e. NVMe) drives for cacheing of video projects / renders, and NOT wasted on the OS. Plus, I wanted to physically separately identify the two NVMe's, and not have them in an 'abstract' Raid setup (apart from the fact that you have to use write-back cacheing to really get the most out of Raid, which ... can jeopardize the stability of your system).
What I don't know:
if the very first time that you boot your new laptop, and you would disable Raid (choose ahci) in Bios, if the installer would still work, so that you don't need a usb drive.
I think that this won't work, since the installer is on the NVMe's, which need Raid in order to run.
But you can try it: very first boot, immediately hit F2, choose Ahci over Intel Rst, see if installation starts, and IF it lets you choose a destination drive.
Again, I think it won't.
Happy computing !