Is VisionTek Ram worth buying?

Maybe something like
http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=6812107&CatId=3361

Or
http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=7025810&CatId=3361

Depends how well versed you are to handling the internal settings of the rig actually.... you could go for the 1.65V ones, but then, there a lot of other stuff that needs to be done in order to achieve the said speeds or else you end up with 1333MHz .... and feel pretty blue about that figure.