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Jun 14, 2021

Ah, is it just me or is the actual script missing from the latest archive file?

Jun 15, 2021

I'm in the same place, no “Virtual_Machine_Compute_Optimizer_v3.0.0.ps1" script inside the zip file.

Jun 16, 2021

Apologies for the oversite. I just submitted an update request, so files should hopefully be updated shortly!

May 07, 2021

We used the VMCO fling to optimize our VMs and made many changes over the past month. A lot of our VMs are 4+ cores, many 8 and 16 cores, and it suggested we move all our VMs to 1 socket and (4, 8, and 16) core setups.

However, our CPU ready time was astronomical... Like 80,000+ ms. Our CPU utilization on each host was only ~25%. We are running single-socket EPYCs host, each with 64 cores/128 threads.

We have since moved almost all of our VMs back to (1) core-per-socket and 4, 8, and 16 sockets. Now our CPU ready time is ~100ms or less for most of our VMs, 300-400ms for some of the heavy hitters.

Since moving back to (1) core-per-socket the VMs feel snappier but we made the changes yesterday and haven't had time to do proper testing. Any suggestions?

May 19, 2021

Heinrich, I apologize for the slow reply! Can you confirm what version of vSphere you are running in your environment? There are some versions that had performance issues w/ the EPYC processors, so a good place to start troubleshooting. See this KB:


May 19, 2021

Mark thanks for the reply. We are using vSphere 7.0 U2 ( and have AMD EPYC 7742 (Rome) processors.

We looked through this guide (Page 27)

We followed these recommendations:

- NUMA nodes per socket = 1
- CCX-as-NUMA = Disabled

These past few weeks the systems seem to be running much better, CPU Ready time is down considerably. Unfortunately I don't have a good benchmark test (before/after) to show...

May 07, 2021

Hi Mark,

Where is this recommendation coming from? "The Host Power Policy is recommended to be set to High Performance
for VMs with more than 8 vCPUs"?

Apr 14, 2021

Hi Mark,

Many VMs reported as VMs Optimized "NO". Do we need to consider OptimalSockets and OptimalCoresPerSocket value to fix?

Apr 15, 2021

Hi Karthikeyan,
Yes, when the VM reports NO for Optimized, you can follow the recommendation to reconfigure it so it will be optimized. The recommendation is to start with the "high" priorities and work your way down to the lows. Fixing all the lows is usually daunting, so the best way to attack that is to correct templates and future VMs that are created.