Radeon HD 5970 Single card and Crossfire @ Guru3D
Quote: "It's time to unleash the beast, welcome to a nice feature length review on the latest dual-GPU offering from ATI. What ATI did with the Radeon HD 5970 is to place two RV870 chips onto one PCB. Bridge them, Crossfire them and all of the sudden you'll have 4.3 Billion transistors at your disposal with a whopping 4.6 TFLOPs of raw performance."
Read the review here