I'm running the PNET VM on a ESXi server that's setup on a HP Z800 12-Core Xeon 2x X5675 3.06GHz 96GB Ram 256GB SSD 4TB HDD PC. Could you kindly help me to identify where and which CPU you are referring to.

The Intel® Xeon® Processor X5675 does not support AVX (Advanced Vector Extensions). The X5675 is part of the Westmere-EP microarchitecture, which was introduced before AVX was implemented in Intel processors. AVX was first supported with the Sandy Bridge microarchitecture, which came after Westmere. Sandy Bridge-based Xeon processors, which started to become available in 2011, were the first Xeon processors to include support for AVX.

I checked the cpu Intel® Xeon® Processor X5675 specification. The cpu model does not support avx.
So, the vm under the esxi running on the cpu does not have the ability to running vm with avx support.