Managed to successfully install Macos Big Sur Beta 3 in my compact Cooler Master Elite 120 PC box, even if Ivy Bridge CPU is not officially supported by Apple.
Specs:
CPU: Ivy Bridge i5-3470
GPU: Nvidia GT 740 2gb
Ram: 8gb (2x4) DDR3 1600ghz
Mobo: Asrock H61M Mini ITX
Storage: 120gb Proton SSD
Kexts: FakeSMC, Lilu, AppleALC, GenericUSBXHCI, RealtekRTL8111, USBInjectAll, WhateverGreen.
I previously had successfully installed Catalina in this PC. I restored a Big Sur BETA 1 dmg image on an 120gb SSD and used my Catalina EFI, with some modifications, mainly updating all my Kexts to the latest/dev ones, updating OpenCore to 0.6.0 and changing the SMBios to iMacPro1,1.I booted successfully to Big Sur Beta1 and then I updated to Beta3 without any problem.
What works: Sound, GPU acceleration, USB ports, Ethernet, CD Player, sleep, boot, shutdown.
The Motherboard does not have BT or wifi so I cannot test. Even though I used for some time a USB dongle of Archer together with Chris1111 wireless usb adapter software (updated for Big Sur) and it was working fine.
Guides I used: From Dortania and dmg image from Olarila
Efi folder: https://drive.google.com/drive/folders/1OsdCX8S25QkYLm6gfvAZftq63L5PmrKu?usp=sharing