Performance Challenges on modern Intel Hybrid CPUs with Notes and other applications
Daniel Nashed – 16 April 2026 08:13:46
After moving to a new notebook, my Notes client got very slow when I was in a Sametime meeting or ran other a bit more CPU intensive tasks.
It turns out that Windows is giving the Notes client the slower E-Core CPU cores, which results in a very slow UI responsiveness.
HCL is aware of this and we had a call last week.
If you are running a modern Intel CPU on your workstation/notebook you should read this link for detailed information and a tool
https://github.com/nashcom/nshcpuset
I wrote up all the technical details and a small troubleshooting and work-around tool.
My take away from this is that we have to watch more for the CPU P-Cores then the total number of cores a modern CPU has.
The notebook I got has 2 physical P-Cores with Hyper-Threading + 8 E-Cores.
This doesn't hit Notes alone! We had interesting experiences with VMware workstation before they looked into it.
Darren blogged about the VMware issues he ran into https://blog.darrenduke.net/darren/ddbz.nsf/dx/type-2-hypervisors-and-the-evils-of-e-cores.htm
I am not a fan of Processor Lasso and looked into the APIs on my own to get a clear picture.
Processor Lasso is a too big tool with a lot of options.
You can also use it, but the easier path is to use my small program.
-- Daniel
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