- The host computer is win64bit.
- I want to run a 64bit Linux guest.
- The CPU is AMD 64bit 2-core.
- I couldn't find HyperThreading or VT, or HT option in the BIOS.
- VirtualBox version is: 4.18
However, VirtualBox tells me that I must enable VT/HT for 64-on-64 scenario.
Why is it mandatory?
How else can I run 64 bit guest?
AMD Athlon 64 X2 3800+
code name windsor
socket AM2 940 with AMD-v instructions!
the comments might be correct:
it seems that the CPU supports AMD-V, but the BIOS (award) – doesn't!
in addition to the answer, @kobaltz was correct:
I had to upgrade my BIOS in order to see an option of chaning virtualization support. Support was there, but the BIOS didn't take it into account.
The reason it is mandatory is that in 64 bit mode (called long mode) most 64 bit CPU's don't support what virtualization software requires for unassisted virtualization.
From wikipedia x86 Virtualization: