New to BI, making sure this will work. i5-6400 ebay find

[c-bolt]

I posted in the other general hardware forum, but no answers there.

Currently, I have the Lorex LHV51082T4K.
4k analog BNC, 8 Channel, 2TB HDD DVR
I think its the LVH5100 series.
4- 4k 8mp deterrence (with the dumb little led light) cameras. model LBV8543X

I am recording at 7 fps, so

7 fps x 8mp x 4 cameras = 224 mp/s

according to what I saw in the wiki, this looks like it will work just fine. I should be able to add IP cameras at a later date as well correct?

Are there any reasons I should not buy this?

Daktech ASUStek INTEL CORE I5-6400 2.70GHZ 1TB 8GB RAM Win 10 Pro Desktop | eBay

Thank you for the help!