Wow, that does seem high - I have an 840 Evo that gives around 1000MB/s in Magician, which I understand is typical... I presume this is connected by a Sata III port? Can I ask what mobo you're using?
Try using Aja DiskspeedTest - it's a free download. Blackmagic also have a similar tool, and there are others. Bottom line is, different tools will test differently and yield varying results as such