This may or may not help people but I’ll leave through trial and error what worked for me in the hope it might help someone else.
I have a dual boot PC with Windows 7 and Windows 10 installed on a Crucial M550 SSD and an Asus P6X58D-E motherboard (I also have other non SSD hard-drives in my system). Both OS worked without issue in IDE mode but I enabled AHCI through the BIOS to speed up the drive. Windows 7 was fine but for Windows 10 it introduces a major issue that froze the PC when it was idle for a few minutes. The mouse would move but it wouldn’t respond and had to be rebooted. No change of LPM or HIPM/DIPM settings would fix it and I also have the latest BIOS and SSD firmware as of Nov 2016.
As suggested above, I was able to switch between IDE and AHCI via a first boot in to safe mode to load the correct drivers each time and then a further reboot.
However, in the Asus BIOS for the P6X58D-E there are TWO settings for AHCI and as soon as I used a combination of IDE and AHCI rather than just AHCI, the freezes stopped happening:-
Storage Configuration -> SATA Configuration [Enhanced] -> Configure SATA as [IDE]
Advanced -> Onboard Devices Configuration -> Marvell 9128 Controller [AHCI Mode]
The combination above loads a combination of ATA Channel, Intel(R) ICH10 Family Serial ATA Storage Controllers and Standard SATA AHCI Controller for my hard-drives under IDE ATA/ATAPI controllers. The AHCI configuration that was freezing just loaded two Standard SATA AHCI Controllers.
I bench marked the SSD in this configuration and it is running at super fast speeds of AHCI (400Mb/s) but with the same stability I had in IDE mode.
Good luck – I was scratching my head for this for hours!