as for the raspberry pi debate
RasPi 2. 900mhz
1gm ram
RasPi 3 1.2ghz (33% increase)
1gb ram
33% increase in processing speed in just 1 year..
say rasPi2 could handle 2000 signature verification's every couple minutes.(understatement used for basic maths)
rasPi3 can handle 2660 signature verification in the same time.
Wait; that doesn't take into account the quadratic growth aspect. The correct calculation is, if rasPi2 can do 1 sigop in t and 2000²*t in a couple of minutes then rasPi3 can handle 1 sigop in 0.75t (maybe) and so in those same couple of minutes we have to solve;
X²*(0.75t) = 2000²*t
X=2309
Certainly a nice increase but not 2660. Does sigop verification scale linearly with GHz?