Intel(R) Pentium(R) 4 CPU 1.60GHz
CPU speed: 2208.00 MHz
CPU features: RDTSC, CMOV, PREFETCH, MMX, SSE, SSE2
L1 cache size: 8 KB
L2 cache size: 512 KB
L1 cache line size: 64 bytes
L2 cache line size: 128 bytes
TLBS: 64
Prime95 version 23.7, RdtscTiming=1
Best time for 384K FFT length: 16.590 ms.
Best time for 448K FFT length: 19.628 ms.
Best time for 512K FFT length: 22.355 ms.
Best time for 640K FFT length: 26.689 ms.
Best time for 768K FFT length: 32.544 ms.
Best time for 896K FFT length: 38.354 ms.
Best time for 1024K FFT length: 43.205 ms.
Best time for 1280K FFT length: 56.681 ms.
Best time for 1536K FFT length: 69.826 ms.
Best time for 1792K FFT length: 82.552 ms.
Best time for 2048K FFT length: 94.037 ms.

我覺得是跟浮點運算有關
P4的FPU比AMD強多了