i currently have an overclockers motherboard bundle Asus P8Z68-V Intel Z68 (Socket 1155) DDR3 Motherboard with Kingston HyperX Genesis Grey 4GB (2x2GB) DDR3 PC3-12800C9 1600MHz Dual Channel Kit (KHX1600C9D3X2K2/4GX). i want to increase the memory to 8gb+. would it be best to add 4 or 8gb to my current sticks (and if so which ones!), or should i buy a new memory bundle (8gb) to replace them (if they wont all work together?). can anyone tell me what to choose for my setup. i currently have an i5 2500k cpu on a 64 w7 system. (want to upgrade as i want to play x rebirth and specs say it recs 8gb memory!). any advice on good memory deals for my system for under £80????