This is a known issue that affects ESXi 5.0.x. For more information, contact VMWare.
To work around this issue, manually create a CPUID mask for the affected virtual machines. To do this, follow these steps:
Turn off the virtual machine.
Right-click the virtual machine, and then click Edit Settings.
Click the Options tab.
Under Advanced, click CPUID Mask.
In the Register column, locate the edx register under Level 80000001.
In the Value field, enter the following character string exactly:
Click OK two times.
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