Firstly - Given your reported use of the computer I strongly doubt that replacing the video card will help - unless you just happen to have some dire video driver issue at present that the new card and possibly software makes go away.
I work with computers but I am not a desktop expert rather a Network Engineer and I have done a bit of pre-windows stylee programming.
From my personal experience a windows installation just seems to slow down over time. Eventually drastically. The recommended solution by the desktop geeks seems to be a fresh windows installation every year or so. To me as a user this is completely unacceptable - it turns out that I would rather suffer the slowness.
I have tried every recommended "fix" (short of re-installing) under the sun and nothing seemed to help. Then one day my next door neighbour who I knew to be suffering from crawling PC syndrome (TM), which I couldn't fix, called me for help. His user profile was broken and the machine refused to log him on.
I was able to create a new user for him and to move all of the files over. The shock was that the old slow windows installation was completely rejuvenated. PrestoChangoSelector all cured.
I have subsequently carried out the process on a (very) few other PCs with fabulous results.
To avoid potential issues if you have to do this ALWAYS install any software for "All Users".
I have also recently had to disable automatic windows updates due to a performance issue that I could not fix. Since it was a pretty good going Notebook - i5, 6G ram and ssd I think that the user experience was still OK but the CPU was permanently high which made the fan run and made my lap hot.
I think it worth checking the integrity of the operating system with
chkdsk (/f with heart in mouth if errors reported)
To be fair I have run this (chkdsk /f) hundreds of times and have never broken a computer with it but in theory in just might. On the other hand continued use of the disk with it unfixed may be riskier still. So there is no real choice.
sfc /scannow
and then if unfixable errors reported
dism /online /cleanup-image /restorehealth
I think you need to be connected to the internet for this as I suspect it gets the files via the Windows Update system.
then if dism reports fixes carried out
sfc /scannow
all from Administrator level command window.
If errors are still reported Windows files are corrupt and there is no real alternative to a re-install.
Finally one that you don't see mentioned all that much is to check that the pagefile is not fragmented. Mind you with 16G ram I don't see that being an issue in your case unless you are doing 3D modelling or some such:-)
PS
ALWAYS have a spare Administrator user set up on the machine since a user profile can get corrupted at any time and you will not be able to log on with it. You can always re-set the password with your handy Linux USB bootable thingy - oops , you didn't encrypt the file system did you? Ah! Best not forget the password then.
Last edited by jimjim1; 14th Nov 2017 at 07:45.