That i5-7400 is at the low-end of the Kaby series. It's not much faster than the 2010-era desktop that I junked last year. So I think that some CPU improvement is in order.
So ... can your board handle a replacement CPU? For around $300 you can get an i7-7700K ... but someone else here will have to say whether it's compatible. (I don't know the sockets.)
Or maybe recommend some other CPU that will fit.
Your i5-7400 clocks in with a PassMark rating of 7400. If your board can only accept i5 processors, then these are the only current i5's that are faster (but I still don't know the compatibility):
Code:
i5-7640X @ 4.00GHz 9692
i5-7600K @ 3.80GHz 9149
i5-7600 @ 3.50GHz 8811
i5-8350U @ 1.70GHz 8199
i5-7600T @ 2.80GHz 8130
i5-7500 @ 3.40GHz 8085
And even that 7640X is only 31% faster. That's enough to notice, but I'd rather spend the money on a whole new box with an i7 processor ... and thereby get some real, meaningful performance gain.