I'm trying to perform FFT for large set of samples,

Sampling Rate : 1 MHZ

No. of Samples Captured : 1 Million (1 sec duration)

currently what I'm doing is, I've added zero padding so that it matches to 2^n, and now the total number of samples are 1048576 (2^20) and then I perform FFT. This approach seemed to take long.

I'm just wondering if there's any efficient way to do this? (Please note that at this stage, I'm not particular about the frequency resolution)

Many Thanks for your time..:)