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The impact of Meltdown and Spectre patches on Windows 7

Meltdown and Spectre

In my previous article I outlined how Windows 10 scalability is affected by the Meltdown and Spectre patches delivered by Microsoft. From our customers and the community, we got messages that Windows 7 (via Citrix XenDesktop or VMware Horizon view) would be impacted more than Windows 10 so obviously that one was next to be put through its paces in our labs. 

As with the previous tests the lab setup is straightforward, however because Windows 7 x64 has smaller hardware requirements I’ve switched from running the test with 180 virtual machines to 220 virtual machines with 1.5GB of memory.

Results:

The results show clearly that just the Microsoft windows update has a very significant impact on both scalability and performance however keep in mind that the updates on the hypervisor and the microcode have not been applied yet. Therefore, it’s my expectation that when applied we will see the results go down again, but for now the question remains: How much? It’s also important to note that I’m testing in a clean lab environment, mileage might vary on your production machines.

To allow everyone to repeat these tests in their own environment Login VSI has decided to offer free licenses to all that want to test the impact of Meltdown and Spectre in their own environment helping the EUC community.

Meltdown and Spectre

To fully understand the results a basic understanding of the VSImax and VSIbase is recommended, please check the Login VSI documentation if you are not familiar with these numbers.

VSImax = The number of users that can work on a system comfortably before performance is impacted (scale). Higher is better.

VSIbase = The performance of the system when there is little or no stress. If this number increases overall performance decreases. Lower is better.

I’m also interested to see how the patches will evolve over time. Since release Microsoft has already updated their patch, Citrix has pulled their XS13 update and provided a new one, whereas VMware currently advices not to update at all.

The lab

Automate, Automate, automate. In our VDILIKEAPRO test lab we have minimized human interaction (and thus error) by making sure all processes are executed fully automatic for example the base images are created using the Microsoft Deployment Toolkit where after PowerShell magic (thanks Henk & Sonny!) takes over and automatically clones the VM’s 220 times, prepares them for use, and runs 10 automated test cycles results are then averaged ignoring the first run.

Login VSI Laboratories Meltdown and Spectre

Infrastructure windows7

Next up:

Tests with updates applied to the hypervisor and a more detailed look into the performance impact on Windows 7 and Windows 10 plus what’s causing it. All new blogs and tests will be featured in our newsletter, sign up here.

About the author

Mark Plettenberg (@markplettenberg) is a product manager of Login VSI and has played a critical role in the development and growth of Login VSI. Ask Mark about motorcycle mechanics and breaking/repairing anything and everything that has a power plug.


Tags: Login VSI, Spectre, Meltdown, Windows 7