Was this an upgrade or a clean install?

You could try setting a static page file. That supposedly helped some people.
https://fossbytes.com/how-to-fix-slo...-system-speed/

So you updated the video drivers and the Hauppauge software? Did you check Hauppauge support about Win10? You didn't say which tv device you have or what version of software you are using.

It also seems that everything has to be run as administrator even though I have local administrator.
Yup. That's how it is with Win10. You can try this:
https://www.cnet.com/how-to/always-r...in-windows-10/