[hpsdr] which CPU to buy...

[Ken N9VV (Android Tablet)]

Let me offer a practical answer; 
Go to your local Wal-Mart and buy a computer system you can easily afford - such as a refurbished Dell or HP. Bring it home and benchmark it with whatever OS and application you wish.  If it seems sluggish, return your purchase with no questions asked! Buy a different CPU and try again until you are satisfied!  

Do *not* rely on these old-timer with experience from 1990. The application is probably *not* compiled with any optimization.  Simon (author of SDR-Console) and Phil N8VB (inventor of the QS1R) use the various Intel Performance Primitives, ICE, and BOOST libraries, but other authors do not. 

YMMV,
GL de Ken N9VV