抱歉我查了一下，2樓給的應該就是答案了
顯示卡需要支援AMD Eyefinity Technology

CCC就會有"建立顯示器群組"

裡面有寫
http://www.amd.com/us/products/tech...Pages/faqs.aspx

所以HD48xx應該是不行用的

What products support AMD Eyefinity technology?
AMD Eyefinity technology was introduced in AMD's latest line of ATI Radeon™ HD 5000 Series graphics products which includes the following:

AMD Radeon™ HD 6870 GPUs
AMD Radeon™ HD 6850 GPUs
ATI Radeon™ HD 5970 GPUs
ATI Radeon™ HD 5800 Series GPUs
ATI Radeon™ HD 5700 Series GPUs
ATI Radeon™ HD 5670 GPUs
ATI Radeon™ HD 5500 Series GPUs
ATI Radeon™ HD 5450 GPUs
ATI Mobility Radeon™ HD 5400 Series or higher GPUs