The workload I'm interested in is transcoding video. I'll reference your links to learn more.Thanks!
More memory, fast memory and fast disks will help roughly in that order.
btw, if I were buying more memory for an XPS 8700 -- and needed faster memory, then I would buy this memory.
www DOT newegg.com/Product/Product.aspx?Item=N82E16820231628
for video, I think I'd run 32GB.
Bingo! That's what I need to know. I didn't realize they made 1600 in CL7. Fabulous!