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Dr4g0n36
02-03-2016, 12:09 AM
Since the 213 BIOS version is out, adding chance to select wich mode have to operate Intel chipset (AHCI or RAID), i have a few question before touch something (at this moment i'm preparing a GPT USB key with Windows 10 update 1511 to test some of my ideas); i hope someone can solve my questions:

Already tried:

Simply change from AHCI to RAID --> blue screen


To try:

Edit registry to add AHCI driver (old workaround)
Clean install of Windows 10 with AHCI protocol (EDIT: SEE BELOW)

Unknown points:

Is the Samsung PM951 (NVME) compatible with AHCI protocol?
What are the PROTOCOL differences between ACHI and RAID? wich is better for G752 models?
AHCI protocol has some limitation regard RAID protocol or reverse?
AHCI and RAID selection are under Intel chipset section, as you can see in the photo above, there's no NVME list, so this option doesn't affect NVME channel?


My channel configuration is this:
SATA1: 1TB HDD SATA3
SATA2: DVD RW
NVME1: Samsung PM951 128GB
NVME2: empty

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EDIT:
After completing USB key i've found that setting BIOS into AHCI mode and booting from UEFI USB key the Samsung NVME is naturally recognized (if you read my previous thread you had to load Intel RAID driver to recognize NVME drive) as you can see from the photo. Still have to find if is better to keep actually RAID or change and re-install into AHCI mode.

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Dr4g0n36
02-03-2016, 12:51 AM
Found THIS (http://forum.notebookreview.com/threads/trying-ahci-mode-xps-15-9550.785081/)very useful thread that's similar to my question. I paste here tests and explain.
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"Green enclosed tests were what I thought best performance and no Sleep/Battery related issues. Orange enclosed tests seem to have some degree of Sleep/Battery related performance drop-off, although this may be subjective. (Note file name prefix numbers were just to order the tests - they have no meaning.)"
(thanks to "techgee" from notebookreview)
SO if someone hasn't any more depth reason to change to AHCI, is better to keep RAID protocol. No need to format, not significant performance increase, AHCI is a son of RAID and keeping in RAID mode can grant me a future update with another nvme using Intel RST program.

tiphon
02-03-2016, 08:35 AM
Hello Dr4g0n36,

I did the same as you. You don't have to reinstall Windows when switching to AHCI, Here is how I did to solve that blue screen.

In windows, use the following command in a command shell (administrator) :
bcdedit /set {default} safeboot minimal

Now restart your computer and switch to AHCI in the bios.

Windows will boot in safe mode.

Now discard the safe boot,

bcdedit /deletevalue {default} safeboot

Reboot and now you have a fully working Windows in AHCI mode without reinstalling anything.

Windows uses default NVMe drivers, you can now install Samsung NVMe drivers

Dr4g0n36
02-03-2016, 09:09 AM
Hello Dr4g0n36,

I did the same as you. You don't have to reinstall Windows when switching to AHCI, Here is how I did to solve that blue screen.

In windows, use the following command in a command shell (administrator) :
bcdedit /set {default} safeboot minimal

Now restart your computer and switch to AHCI in the bios.

Windows will boot in safe mode.

Now discard the safe boot,

bcdedit /deletevalue {default} safeboot

Reboot and now you have a fully working Windows in AHCI mode without reinstalling anything.

Windows uses default NVMe drivers, you can now install Samsung NVMe drivers


Ok, this is "how". I need "why".

Also there's another method to enable AHCI.

open REGEDIT as admin
navigate to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\servic es\msahci
change value to 0
if present, locate also HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\servic es\iaStorV and do the same (value to 0)
reboot to BIOS and select AHCI
reach desktop and reboot after new driver load.

diogogmaio
08-22-2016, 11:12 PM
I have to ssd 256gb in my G752VY and they are with RAID on BIOS 213...default.
Should I enable RAID0 because of the two equal ssd of 256gb each?
It is better?
Can someone help? In BIOS, RAID0 it is disabled.

JustinThyme
08-23-2016, 03:52 AM
You can make them into a raid 0 array but its not as simple as just enabling it. There are other threads here adressing this specifially on the G752VY, not the VT that is being discussed in this thread.
If you have two equal size drives raid ) will give you one drive that is the sum of the two. Theoretically its twice as fast but realistically two of them pushes the limits of the bus that is 3GB/s What I get with 2 512GB Samsung M2 950 pros is just short of 2.9GB/s sequential read. Where I was getting 2.4 without raid 0. Improvement, yes but not twice as fast due to limits of the bus.
What you do see though is a drastic improvement in write speeds!
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