I found something that I think is telling about this: 

 

 

Did some googling - think it might be this: ram initialisation is O(n)

For me I went from 5 - 10min VM boot load to about 30 seconds. SeaBIOS was incredibly slow to boot the VM but once I transitioned the system to UEFI I can now boot with a usable speed.

 

The steps I took to resolve the problem were;

 

• Backup your vdisk. Reduce your problematic VM CPU core count and RAM (4 cores, 8GB worked for me). Run the following commands in the windows VM which is slow to boot. This prepares the system for UEFI booting. 

   

// The first line checks if your system is valid for UEFI
mbr2gpt /validate /allowFullOS

// The second line will convert your boot to UEFI (less than 1m)
mbr2gpt /convert /disk:0 /allowFullOS

 

• Enable Unraids UEFI boot under the flash device settings. 

 

 

• Enable UEFI in motherboard (leave CSM enabled).
• Reboot the server.
• Create a new VM changing SeaBIOS to OVMF and whatever RAM/CPU core count you desire. Point the vdisk to your old image.

 

Please let me know if this works

Edited May 6, 20224 yr by wolfNZ