1.  Yes, if you add an 8G to the onboard 8.  If you add a 16, 16 will be dual channel;  8 will run single channel. 2. CL-22  
Hello. Just 2 questions:1. Does it support dual channel (is unclear on user manual on site)?2. What are the soldered ram timings? Thank you in advance.
Dell 7501 Ram Info