Understanding the performance impact of Spectre and Meltdown mitigations on Windows Systems

So, regarding Terry's post, specifically:  "With Windows 8 and Windows 7 on older silicon (2015-era PCs with Haswell or older CPU), we expect most users to notice a decrease in system performance."

Does anyone have any real-world experience with the level and extent of user complaints or the lack thereof when using Intel I7 Core (i7-3820QM CPU@ 2.70Ghz) pre 2015 era laptops?

In our environment, these users do mostly Office (All Apps), Office 365 for Business, and other Cloud Based Apps.

Any input would be greatly appreciated.