Hi again
Your memory usage sounds reasonable, especially if you have a system with 4 GB of system memory. About 1.3 to 1.6 GBs in use isn't too unusual. Some Draconian trimming can sometimes get the usage down just below 1 GB, but opening a browser with a fair amount of tabs in use can boost it right back up to the 1.6 GB range.
I'm guessing your slowdowns are cpu/disk usage based. You can make sure that you don't have services running that you don't want (if you don't need the "Windows Media Player Network Sharing Service", for example, that is a service that can use a fair amount of cpu/disk resources -- I've seen it show spikes of high usage on computers of my customers who never in a million years would have needed it). Other things to look at: check to make sure only the defaults are being indexed for Windows Search (Control Panel - Indexing Options) ... indexing stuff you don't need indexed is a sure waste of resources. If you don't use Cortana, you can turn Cortana off, and just use plain old Search (you can always turn Cortana back on should you wish to).
Since you have the Nvidia streaming game service running, see if uninstalling the Nvidia drivers - and then reinstalling the latest version - using the "Custom" install method, and the "clean install" option, and opting out of the unnecessary add-ons - helps. It has for some users.
_______________
High memory usage doesn't usually slow you down much until it's well over 60% or so. High disk and cpu activity, on the other hand, can be noticeable as low as 40% or so. Up around 90% usage for disk or cpu is when we start drumming our fingers to pass the time waiting for things to speed up.
It is an option to uninstall the update (Start-Settings-Updates & security-Windows Update-Advanced Options-View Your Update History-Uninstall updates). It takes a while, but several users report seeing their systems running normally again after removing the update. If you choose this route, you might want to:
1) Download and use a Microsoft tool to let you block a particular update from installing
https://support.microsoft.com/en-us/kb/3073930
Or
2) [if you have Windows 10 Pro] Use Group Policy to configure Windows Updates to notify you and let you choose whether to install
Disable / Turn Off Automatic Updates In Windows 1 , Here's How | Redmond Pie
If you choose the uninstall/block route, I'd recommend checking fairly regularly to see if the problem is resolved with a follow-up update. Usually when a Windows Update has a bad effect on enough systems, Microsoft will patch the problem with a follow-up update. If/when that happens, you can set updates back to Automatic if you'd like.
Let us know if you have questions
