There are VRMSpec versions, such as 8.1 conformity, 8.2 conformity, 8.3 conformity, and 8.4 conformity.
Larger conformity means you'll be able to use a faster processor.

In the case of CPU beyond this, it becomes unstable although dual operation of the VRM of 8.1 conformity is carried out satisfactory
if a clock frequency is CPU to about 450MHz.
However, there is also an example of a report of having stabilized and operated by VRM of the 8.1 conformity by 550MHz CPU.
If it is VRM of 8.3 conformity or 8.4 conformity, dual operation is possible at CPU of a 1GHz clock frequency.
 

However, even when it is dual and uses 1GHz CPU, it may not pass over this
in the meaning that it has been the thing of 8.3 conformity or 8.4 conformity enough as spec. of VRM demanded, and it may not operate by the production time or the production country of the CPU itself. However, this is not the problem of the VRM itself but the problem of the CPU itself to be used.

Determining your VRM module Type

pull your module out. Where it connects, there is a label. When the connector faces towards
the floor, at the bottom right there is something like this:

VXI P/N: 073 20742 30 REV:B

VXI is the company. What matters is the sequence 20742 30, nothing else.

Now look it up in the table (big thanks to the japanese usergroup)


PartNumber VRMSpec Vin(VDC) Vout(VDC) Iout(A)
VXI-20715-02 VRM8.1 5 1.8-3.5 14.0
VXI-20737-02 VRM8.1 12 1.8-3.5 14.0
VXI-20740-01 VRM8.2/8.3 5 1.3-3.5 16.0
VXI-20742-30 VRM8.2/8.3 12 1.3-3.5 16.0
VXI-20742-20 VRM8.2/8.3 5 or 12 1.3-3.5 16.0
VXI-20750-01 VRM8.2/8.3 5 1.3-3.5 16.0
VXI-20754-02 VRM8.2/8.3 12 1.3-3.5 16.0
VXI-20755-01 VRM8.2/8.3 12 1.3-3.5 dual output 16.0x2
VXI-20770-01 VRM8.2/8.3/8.4 5 1.3-3.5 19.0
VXI-20771-01 VRM8.2/8.3/8.4 5 or 12 1.3-3.5 19.0
VXI-20772-01 VRM8.2/8.3/8.4 12 1.3-3.5 19.0
VXI-20773-01 VRM8.2/8.3 12 1.3-3.5 dual output 16.0x2

so this example would be 8.3 compliant.


With a VRM of 8.3 conformity or 8.4 conformity, dual operation is possible at CPU of a 1GHz clock frequency.