Either I’m just too used to slow machines, or my Phenom II X4 (and previously my Athlon II X2) has no real issues running Haiku on VirtualBox (6.1.14, 6.1.40, and now 7.0.2).
I’m using real HDD/Partitions as storage… the rest of my VBox settings are pretty straight forward:
4 Cores, 2048 MB of RAM, 32 VRAM, VT-x/AMD-v, Nested Pagination, PAE/NX, KVM paravirtualization (that’s due to using the same VM to access a Linux install on that HDD).
VMSVGA graphics (as recomended by VBox), installed vmware_addons on Haiku to make use of that graphics driver.
ICH97 for audio, Intel PRO/1000MT Desktop for LAN (bridged).
My only complain, performance wise, is with large filesystem operations (deleting/stating big repo trees),but that also happens when running on bare metal, and only under Haiku, so, not a VBox issue.
Edit: just to clarify… I use VBox 7.02 on Win 10 LTSC 2021 (Hyper-V or WSL not even installed) most of the times with no real performance issues. Not much different from my old Linux install with 6.x there.