Older CPU outperforming newer on ESXi 5.0?

[hayner]

We have several generations of servers running ESXi. The bulk of them are Dell, either r710s or r810s. Looking at the data from NovaBench, the CPU in the 810 should solidly outperform the one in the 710:

CPU Name                            Avg. Score            Avg. MHz           Sample Size

Intel Xeon X6550 2.00GHz      754                       1996                   4           <-- r810

Intel Xeon X5570 2.93GHz     582                  2871                   27         <-- r710

So to my understanding, the x6550 should be faster, even given the slower speed. Is that correct, or am I misinterpereting?

Running the NovaBench test on a test VM running on these ESXi hosts shows the reverse is true:

r810:

NovaBench score: 234

CPU Test Score: 121

r710:

NovaBench score: 301

CPU Test Score: 168

Can anyone help me to understand what's going on here? Let me know if more details are needed or if I was unclear in describing.

Thanks in advance,

-Chris

[hayner]

We are using EVC, with the "Intel Merom Gen. (Xeon Core 2)" mode

[sparrowangelste]

given that a core on the X5570 is faster then that one would perform better.

how many vcpus were given to the vm?

[hayner]

So you're saying that it's just a pure speed issue then? Do you know what would explain the official NovaBench score being higher for the newer (slower) CPU?

The test VM had 1vcpu, 2G ram. W2k8r2 with nothing else running on it.

[sparrowangelste]

the reason the offical score should be higher is because it's probably using all its cores and optimizations.

you are using 1 core with evc.

a vcpu is only 1 core.