Can I Use UEFI BIOS To Boot To MBR Discs With 32-Bit Windows 10 Pro?

travasaurus

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Jan 21, 2010
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I have a reasonably new Dell XPS 8900 which is currently using Legacy BIOS boot mode and has a 256GB Samsung SSD boot drive and a couple of Seagate 2TB drives in a RAID 1 configuration as the "D:" drive which I use for redundant backup and storage. It's currently running 32-bit Windows 10 Professional with all drives formatted with the MBR file system. I'm going to upgrade to a new Samsung 960 EVO 1TB boot drive with NVMe and it supposedly needs UEFI activated to work at top speed. I'm planning on keeping the 32-bit version of Win 10 Pro and (since none of the drives are over 2TB) the MBR file system scheme. The new Samsung SSD will be the boot drive. My question is, since I apparently have to use the UEFI BIOS setting to make the SSD work right, will I have a problem continuing to use the 32-bit version of Windows 10, as well as the MBR file system? According to Samsung the SSD will work in Legacy BIOS mode but I won't realize the performance boost given by the NVMe technology, which they say can only be activated by using the UEFI BIOS boot mode. Thanks & standing by...
 
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Its not a problem I was aware of with nvme drives, I know GTX 10 series cards need UEFI Bios to install but that is probably not related to this, just means you can't put them in PC older than 7 years.

GPT discs meant to be harder to break boot process on that MBR discs but I can't say I have noticed.

Colif

Win 11 Master
Moderator
Only if you lucky. Most UEFI are 64bit so you need a 64bit os to match the UEFI, You would need a 32 bit UEFI to install win 10 32bit

An EFI install of Windows 10 32-bit can be performed on systems that are operating in 32-bit EFI mode, which isn't related to your make/model of processor. You'll have to consult your motherboard manufacturer/instructions to determine what version of EFI support your motherboard shipped with and if you can tweak it.
Typically, newer devices ship with a 64-bit EFI without a toggle to change that. (Which means no native install of Windows 10 32-bit will be possible.) Some, however, ship with a CSM option that kicks in the older BIOS stuff, it'll work, but you don't want that.

https://answers.microsoft.com/en-us/windows/forum/windows_10-hardware/windows-10-32-bit-native-uefi-install-on/c72ff865-859a-43d7-b24c-5e726efba22a?auth=1

You have to fresh install win 10 as 64bit to get the benefit of the nvme. You don't need a new licence, the 64bit version uses same licence, just need to make or use a 64 bit installer.
 

travasaurus

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Well that's not exactly the news I was hoping for; I guess there's a small (but not good) chance that this Dell XPS 8900 mobo might support 32-bit UEFI but I won't hold out too much hope. Now my 2nd question is, if I do have to move to 64-bit Win 10 can I keep the MBR file system (since I don't have any hard drives over 2TB) or will I also be forced to convert to the GPT file system, at least on the boot drive? Will 64-bit Windows recognize a MBR-formatted boot drive? I'm pretty sure Windows will recognize other MBR non-boot drives, such as the standard Seagate 2TB drives I'm utilizing (in RAID 1) as "Drive D" for redundant backup file storage...
 

Colif

Win 11 Master
Moderator
UEFI 64 bit can boot off MBR or GPT as its backwards compatible BUT if you clean install onto a drive on a UEFI system windows 10 will insist on GPT. What that means is its happy to boot MBR drives if you upgraded from an older version of windows but as soon as you clean install it insists on GPT - I know as I found out hard way last year but lucky there wasn't anything on ssd I couldn't afford to lose.

I wasn't sure so 2nd opinion time
When you deploy Windows to a UEFI-based device, you must format the hard drive that includes the Windows partition by using a GUID partition table (GPT) file system. Additional drives may use either the GPT or the master boot record (MBR) file format.

A GPT drive may have up to 128 partitions.

Each partition can have a maximum of 18 exabytes (~18.8 million terabytes) of space.
https://msdn.microsoft.com/en-us/windows/hardware/commercialize/manufacture/desktop/configure-uefigpt-based-hard-drive-partitions

wow at the space... erm, back on topic.. yes, you need GPT on boot drive
 

Colif

Win 11 Master
Moderator
Its not a problem I was aware of with nvme drives, I know GTX 10 series cards need UEFI Bios to install but that is probably not related to this, just means you can't put them in PC older than 7 years.

GPT discs meant to be harder to break boot process on that MBR discs but I can't say I have noticed.
 
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