\[ \boxed { 2\, \left ( {\frac {{\rm d}^{2}}{{\rm d}{x}^{2}}}y \left ( x \right ) \right ) y \left ( x \right ) - \left ( {\frac {\rm d}{{\rm d}x}}y \left ( x \right ) \right ) ^{2}+3\,f \left ( x \right ) y \left ( x \right ) {\frac {\rm d}{{\rm d}x}}y \left ( x \right ) +2\, \left ( \left ( f \left ( x \right ) \right ) ^{2}+{\frac {\rm d}{{\rm d}x}}f \left ( x \right ) \right ) \left ( y \left ( x \right ) \right ) ^{2}-8\, \left ( y \left ( x \right ) \right ) ^{3}=0} \]
Mathematica: cpu = 0.550070 (sec), leaf count = 54 \[ \text {DSolve}\left [2 y(x)^2 \left (f'(x)+f(x)^2\right )+3 f(x) y(x) y'(x)+2 y(x) y''(x)-y'(x)^2-8 y(x)^3=0,y(x),x\right ] \]
Maple: cpu = 1.217 (sec), leaf count = 0 \[ \text {could not solve} \]