I must say, the guy that tried to prove that Spica's CPU is better was right. No reason to try to prove otherwise. For once and for all, Spica has a faster CPU. Here is some proof:
Samsung Spica I5700 C5Bench
http://www.c5bench.com/results/ (top are fastest, bottom are slowest)
Benchmark Tests C5Bench (tests are explained)
To sum it up. Spica with 2.1 had a sum of 454fps, 1.5 Spica had a sum of 331fps. i7500 uses the same CPU as Magic, Dream or Hero. Magic had 241, 254, 255fps, Dream had 252, 258fps and Hero had 309, 319fps.
There was a debate that i7500 has dual core. It has infact, one ARM11 at 528MHz and one underclocked ARM9 at 250MHz. But ARM9 is used ONLY for radio and is not available to the OS. So it's of no use when we look at the benchmarks.
Spica's CPU does indeed have one core. Radio probably has a dedicated chip, something like iPhone which probably is a stadnard ARM9. Galaxy's dual core should, as I mentioned, be taken with a pinch of salt because the other core isn't available for every day usage.
Anyway, this is Spica's CPU:
SAMSUNG's Digital World
It's clocked to 800MHz. It even has dedicated 3D acceleration capable of OpenGL ES 2.0, like the Droid.