\[ y'(x)=\frac {1}{2} x^2 \left (2 \sqrt {x^3-6 y(x)}+1\right ) \] ✓ Mathematica : cpu = 0.195288 (sec), leaf count = 38
DSolve[Derivative[1][y][x] == (x^2*(1 + 2*Sqrt[x^3 - 6*y[x]]))/2,y[x],x]
\[\left \{\left \{y(x)\to \frac {1}{96} \left (-16 x^6+8 x^3-192 c_1 x^3-1-576 c_1{}^2-48 c_1\right )\right \}\right \}\] ✓ Maple : cpu = 0.275 (sec), leaf count = 23
dsolve(diff(y(x),x) = 1/2*x^2*(1+2*(x^3-6*y(x))^(1/2)),y(x))
\[c_{1}-x^{3}-\frac {1}{2}-\sqrt {x^{3}-6 y \left (x \right )} = 0\]