Your psecs look good to me although I agree that the interface is a factor in latency.
 
I see you are opting for an SSD.  If, like me, you will be using large orchestral sample libraries like Vienna or Hollywood, I believe an SSD is an absolute requirements since the samples stream from disk and a spinning disk can't keep up.
 
I use rotational for storing projects and SSD for large sample libraries.

+1 on Konrad's drive advice.

• For boot drive, SSD is nice (system boots faster, apps open faster).
• For projects/audio, go with a conventional HD.
• Disk-streaming sample libraries is where SSD really shines.  For heavy polyphony situations, you'll need multiple SSDs.  ie: We have a few clients who regularly need 2000 simultaneous voices of disk-streaming polyphony. Multiple SSDs is the only way to achieve this level of performance.  Note:  This is an extreme example... where the client is scoring for video games (doing huge orchestral mock-ups). 

 

RME is has a well deserved reputation for low latency and solid reliability.  Which particular unit is best depends on your particular needs (e.g., # inputs).  

Jim Roseberry
 
There's no DAW related benefit to using Xeon CPUs.
You'll pay significantly more... for a significantly slower clock speed. 

I plan to upgrade my PC  to the newest generation Intel CPU and I was thinking about getting Xeon Skylake when it'll be available. Xeons are in the same price range with i5. So besides prices and clock speed, is there any reason why Xeon can be a bad choice for a DAW and some video editing?