I'm going to buy an i5 4670k processor and I know that intel recommend RAM at 1600. I've been looking looking at a few and even in same speed RAM there are quite big price differences. For example:
http://www.amazon.co.uk/dp/B004I763AW/?tag=pcp0f-21
This is £20 cheaper than this
http://www.amazon.co.uk/dp/B003KWYI8K/?tag=pcp0f-21
http://www.amazon.co.uk/dp/B004I763AW/?tag=pcp0f-21
This is £20 cheaper than this
http://www.amazon.co.uk/dp/B003KWYI8K/?tag=pcp0f-21