From the looks of that link, it doesn't even have a graphics card so you'd be running off the CPU's graphics chip (Intel HD series) which isn't as good as a dedicated card like the R5. The amount of RAM you need is completely dependent on what you want your PC to do. 8GB ram is great for gaming because you can dedicate at least 4gb to the game and leave the remaining 4gb for processing, OS, etc.
Although the second link has a better CPU, its lack of a dedicated graphics card makes it slightly less favorable in comparison to the first link.