yea, that ist the same like if you buy a big truck for your family. Sometimes you will relocate. Then you can take all your stuff and take it with you. All the other time you drive to work with that thing. Very clever. That has nothing to do with the amount of posts to understand that.
Windows is definetly oversized to do a job as a surveillance system. In the background there are running so many task which have nothing to do with your surveillace job. All printing stuff for instance. There are modified window versions which some people created to be optimized for gaming. Everyting has been taken out but graphic. I asked here some time ago if there are special Windows versions for surveillance, but there is nothing. Linux is better but you may have to learn it. Look through their recomandations what you should buy to serve 6 cams or so.
I looked up a small NVR for you to test is, it is below 50$. The only disadvantage, it has no internal disk.
mini NVR
I have the same here in my home. i bought ist used on ebay for about 20$
Buy it and see how easy it is. You will never use a pc anymore for that job.
I can highly recommend this one
SAE3000-N7932F it is very powerfull an is working without any errors for quite a while. And you do not have to sit at the console. My NVR is located in a small chamber with all modem and switches. I can administrate it from any pc in my house on IE.