Well since you're not planning on overclocking, the value ram should be good enough. However if you play games with your pc then get a 2x1Gb value ram for optimum performance. There's a difference on both hyperX and value ram, but it would be just an overkill to use the hyperX due to the cpu. As for the 2x1Gb value ram over the 2x512Mb, it enables you to play games at higher settings. But if this pc is for just your daily use like business, web or personnal applications other than gaming then the 2x512Mb value ram is the wise choice.