Corsair or OCZ probably make single sticks of 4GB DDR3 or dual channel kits of 8GB, but I haven't heard of Corsair or OCZ triple channel 3x4GB kits. Just buy one a 4GB DDR3 stick and an 8GB dual channel kit. Just wondering though, why would you want 24GB? Very few people apart from servers and professional workstations manage to use 12GB or 24GB, and most everyday gamers and amateur video editors won't even use 6GB. Unless you making this computer into one of the two above. Just so you know, there is a massive price difference between a single stick of 2GB DDR3 and 4GB DDR3 RAM.