VB 4.3.8 not detecting full CPU Cores AMD FX 4100

[CaelThunderwing]

was setting up a Windows 8 VM to test te OS to see if i felt worth upgrading from 7 (not in a realtime use but for mostpart testing what programs i allready have etc working/installing under 8)

when setting 4 cpus to the VM im told Invalid settings (stating Host only has 2)

the AMD FX 4100 is a Quad-core CPU not a Dual-core i m not sure the effect of permance this will have on the VM Either :/

[Socratis]

From the log:

00:00:04.680724 Logical host processors: 4 present, 4 max, 4 online, online mask: 000000000000000f
00:00:04.681181 Physical host cores: 2

Your AMD FX 4100 seems to have 2 physical cores with hyper-threading. VirtualBox talks only to physical cores. Plus it's not a good idea to assign all your available resources to your VM.

[Frank Mehnert]

Right. According to some web sites, the processor has 2 physical cores with 2 hyperthreads per core. For counting the processors we do only count physical cores. Actually the GUI warning has no influence about any VM behavior so it would be still possible for you to set up a VM with 4 virtual CPUs (using VBoxManage). However, we strongly discourage from doing so because a VM with 4 virtual CPUs on a system with only 2 physical cores might not behave well (timing issues). That's the reason for the GUI warning.