VMware CPUID README
Overview: The cpuid.iso image can be used to create a bootable CD that
aids in processor and feature identification. Specifically, this tool
will help in determining hardware support for 64-bit guests and CPU
features for VMotion compatibility. The following steps outline its usage:
1. Burn a CD from the image
2. How to run the program:
After the bootable CD image has been copied to a CD-R or CD-RW, insert the
CD directly into the chassis, and reboot the machine. The boot order in the
BIOS may need to be configured so the machine boots from CDROM in the
3. How to interpret the output:
The tool will display Family/Model/Stepping information for the CPUs
detected, and hexadecimal values for the CPU registers that identify
specific CPU features. The hexadecimal register values are then interpreted
to indicate whether the CPUs support features like 64-bit, SSE3, and nX/xD.
Sample output is as follows:
Reporting CPUID for 2 logical CPUs...
All CPUs are identical
Family: 0f Model: 04 Stepping: 1
ID1ECX ID1EDX ID81ECX ID81EDX
0x0000641d 0xbfebfbff 0000000000 0x20100000
Vendor : Intel
Processor Cores : 1
Brand String : " Intel(R) Xeon(TM) CPU 2.80GHz"
SSE Support : SSE1, SSE2, SSE3
Supports NX / XD : Yes
Supports CMPXCHG16B : Yes
Hyperthreading : Yes
Supports 64-bit Longmode : Yes
Supports 64-bit VMware : No
a. 64-bit Support:
On Intel systems, the last line will indicate "Yes" when the CPUs support
EM64T and Intel Virtualization Technology (VT). It's also worth noting that
Intel CPUs may be VT capable, but have the functionality disabled by the BIOS.
The CPU Identification utility will report "No (BIOS feature may enable)" for
those cases, and a configuration change through the BIOS will be required
to enable it.
On AMD systems the last line will indicate "Yes" on any 64-bit enabled
Opteron (Rev E or later). AMD's version of hardware virtualization support
(referred to as SVM, Pacifica or AMD-V) is not required.
b. SSE Support:
The "SSE Support" line will indicate all generations of SSE multimedia
instructions supported by the CPUs. The KB articles listed in the
References section outline how SSE support affect CPU compatibility
c. NX / XD Support:
The "Supports NX / XD" line will indicate "Yes" when the CPUs support
AMD's No eXecute (NX) or Intel's eXecute Disable (XD) technology.
Both variants serve the same security purpose: to mark memory pages as
data only to prevent malicious software exploits & buffer overflow attacks.
All of the following guest OS types can use it when available:
Windows Server 2003 (SP1), Windows* XP (SP2), Windows Vista, RHEL4,
RHEL 3 (Update 3), SUSE 10, SUSE Linux 9.2, Solaris 10, Linux kernels 2.6.6
or later (or 2.4 kernels with a patch).
Strict separation of NX/XD mismatched hosts, however, is not required.
In order to provide more flexibility in dealing with CPU features that
affect VMotion compatibility, and in order to provide a mechanism to
restore VMotion compatibility back to older versions of VirtualCenter
and ESX Server when desired, VirtualCenter will allow customization
at the per-VM & per-Host levels:
* Per-VM compatibility masks for individual VMs to take advantage of
advanced CPU features OR to hide advanced CPU features to maintain
* Per-Host settings to set configurations for ALL the VMs of a particular
guest OS type at once.
This line indicates that 16-byte compare exchange (CMPXCHG16B) instructions
are supported by the CPUs.
e. 3DNow! Prefetch:
On AMD systems, the "Supports 3DNow! Prefetch" line will indicate that
the PREFETCH instructions are supported by the CPUs.
On AMD systems, the "Supports RDTSCP" line will indicate that the
RDTSCP instruction is supported by the CPUs.
On AMD systems, the "Supports FFXSR" line will indicate that the
optimized versions of FXSAVE and FXRSTOR instructions are supported
by the CPUs.
h. Mixed stepping processors support:
On some platforms with Intel mixed stepping processors, a message will
indicate that it is supporpted on some ESX versions. Here is a sample
Reporting CPUID for 8 logical CPUs...
All CPUs are not identical
Detected mixed processor revisions on the system. This
configuration is supported on ESX 2.5.5, 3.0.2 Update 1 and
VMware Knowledge Base articles:
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6,961,806, 6,961,941, 7,069,413, 7,082,598, 7,089,377, 7,111,086, 7,111,145,
7,117,481, 7,149,843, 7,155,558, 7,222,221, 7,260,815, 7,260,820, 7,269,683,
7,275,136, 7,277,998, 7,277,999, 7,278,030, 7,281,102, and 7,290,253; patents
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