Improve CPU performance in VMware ESXi (?)

jtannous · February 9, 2020

Hi guys,

I'm sorry if the question seems a bit lame, but I thought that there's nothing to loose

My specs are:

Intel Core i7 4790k (4C/8T) @ 4.6GHz

32GB Ram

GTX 1070 with some OC

This rig is running VMware ESXi with 1 Windows gaming instance with the following specs:

6vCPUS (6 cores)

14GB Ram

GTX 1070 Pass through to this instance.

I mainly play CoD Modern Warfare, and I'm getting around 80-90 FPS on average (~120 MAX) and I'm clearly CPU capped, as it's around ~95% load during game play.

I tried to increase vCPUS to 7, but, as expected it actually hurt the performance, as it leaves only 1 thread available to the host and the rest of the instances (3 CentOS).

So my question is, does anybody know any genius way to magically increase CPU performance for windows instance in VMware?

Thanks!

jj9987 · February 9, 2020

7 vCPUs likely hurts due to unequal CPU distribution. Your processor has 4 physical cores, each has two threads for a total of eight threads. The most optimal way would be to give the whole core to the VM (so both threads). If you give only single thread, that core will be switching constantly between two different workloads (fetching different data into cache) resulting in a much worse performance.

As for running the game on 6 vCPUs - not sure, I haven't looked into gaming VM on ESXi. I know unRAID allows choosing which specific cores you want to assign to a VM to prevent overlap, however ESXi does not allow you to do that - it does it on it's own to maximize core usage/efficieny. Could be the scheduler not working as optimally, but could also be something else.

To start with - Is that game supposed to be running better with that CPU? Have you tried running Windows and the game directly on the hardware (without hypervisor)?

jtannous · February 9, 2020

That's a great point there.

I'm not sure, but I think that ESXi has the ability you talked about, take a look at the help prompt in the following screenshot:

Based on your theory I should enter the value "0-5" here, Am I wrong?

Regarding the comparison, you are totally right, I should check that. However, I won't be able to check it directly on my system as it will result in a long downtime which I can't afford. But I will totally check for benchmarks online

Thanks!