| input len | real FFTPack | real vDSP | real PFFFT | cplx FFTPack | cplx vDSP | cplx PFFFT |
|---|---|---|---|---|---|---|
| 64 | 2517 | 7995 | 6086 | 2725 | 13006 | 8495 |
| 96 | 2442 | n/a | 6691 | 2256 | n/a | 7991 |
| 128 | 2664 | 10186 | 7877 | 2575 | 15115 | 9115 |
| 160 | 2638 | n/a | 8283 | 2682 | n/a | 8806 |
| 192 | 2903 | n/a | 9083 | 2634 | n/a | 8980 |
| 256 | 3184 | 11452 | 10039 | 3026 | 15410 | 10199 |
| 384 | 2665 | n/a | 10100 | 2275 | n/a | 9247 |
| 480 | 2546 | n/a | 9863 | 2341 | n/a | 8892 |
| 512 | 2832 | 12197 | 10989 | 2547 | 16768 | 10154 |
| 640 | 2755 | n/a | 10461 | 2569 | n/a | 9666 |
| 768 | 2998 | n/a | 11355 | 2585 | n/a | 9813 |
| 800 | 2516 | n/a | 10332 | 2433 | n/a | 9164 |
| 1024 | 3109 | 12965 | 12114 | 2869 | 16448 | 10519 |
| 2048 | 3027 | 12996 | 12023 | 2648 | 17304 | 10307 |
| 2400 | 2515 | n/a | 10372 | 2355 | n/a | 8443 |
| 4096 | 3204 | 13603 | 12359 | 2814 | 16570 | 9780 |
| 8192 | 2759 | 13422 | 10824 | 2153 | 15652 | 7884 |
| 9216 | 2700 | n/a | 9938 | 2241 | n/a | 7900 |
| 16384 | 2280 | 13057 | 7976 | 593 | 4272 | 2534 |
| 32768 | 768 | 4269 | 2882 | 606 | 4405 | 2604 |
| 262144 | 724 | 3527 | 2630 | 534 | 2418 | 2157 |
| 1048576 | 674 | 1467 | 2135 | 530 | 1621 | 2055 |
I double-checked to make sure I did not make a mistake in the time measurements, as the numbers are much higher than what I initially expected. They are in fact higher than the number I get on the 2.8GHz Xeon of my 2008 mac pro.. (except for FFT lengths >= 32768 where having a big cache is useful). A good surprise is also that the perf is not too far from apple's vDSP (at least for the real FFT).