[SOLVED] Win10 x64 EFI-less reinstall caused abnormal boot times

[mwasil]

Hi!
I was reinstalling Windows 10 64-bit on my Asus GL552VW laptop.
Originally, it came with a HDD with a EFI partition on it. I wiped the HDD making it a secondary drive, and bought a M2 drive.
I flashed a USB stick using Media Creation Tool, and reinstalled in on the M2 drive. In order to even boot the installation, I had to:

1. disable Secure Boot
2. disable Fast Boot
3. Enable CSM (compatibility support module)
4. enable legacy boot mode

Reinstallation went fine, OS works as expected, except for boot times.
It takes over 40 seconds to boot, while on a normal PC without the EFI partition it literally takes 4 seconds to boot Win10 from an NVME drive using a"standard", EFI-less bootloader.
The problem is, I cannot disable CSM, and/or enable the rest of the options, because the laptop won't boot to OS. It simply drops to BIOS.

Shall I try to reset the BIOS? Will it change anything?

EDIT: I think i made the thread in a wrong section, can someone please move it?

 

[Colif]

where do you think it should be?

what is slow, before or after bios screen?
updating chipset drivers can fix speeds if its after the boot screen.

 

[mwasil]

UPDATE: nevermind, I already fixed it. I used mbr2gpt and it worked
The slow boot was caused by the BIOS launching the CSM. After converting the disk from MBR to GPT/UEFI, the laptop can now FAST BOOT again, booting in 7 seconds