Hey,
You can EXPERIMENT, but basically if your video isn't STUTTERING then there's nothing to worry about.
You can also open the TASK MANAGER (ctrl-alt-del) and look at "Performance-CPU" though change graphs to show all (two) because you want to see if any single core is running close to 100%. If you hit 100% you'll get stuttering. Average across two cores is useless for this scenario.
You should be okay, but if any program kicks in like anti-virus you'll have stuttering issues for HD content. I tested a slightly weaker CPU and it was having issues with HD content but it was pretty close.
*I then added a cheap HD6450 graphics card, installed K-Lite Standard, then the content played just fine.
K-Lite:
http://www.codecguide.com/download_kl.htm
**For K-Lite (for your own content) you'll want to enable hardware acceleration. I'm not sure what your current GPU supports but the GT730 should support the main content of H.264, MPEG2, VC-1.
Summary:
- Task Manager can show CPU usage (100% on any core is bad)
- K-Lite Standard (enable hardware acceleration on install or under "options-> Internal Filters"
- web browser plugins should default to hardware acceleration (you can right-click to see)
Other:
If you have W7 or W8 then W10 might help. I say might. For two reasons:
a) clean install (even if just upgrading that's "cleaner"), or
b) better memory management
Probably pretty similar though. I had W7 on an older PC (X2-4800+ CPU, + HD5450) and it's running much better with Windows 10 though I'm almost certain most of that is because W7 software had issues of some kind. Whatever, it's working better now and my BSOD and other issues are finally gone on all my W10 machines.