Did a bit more digging around in my Spica, lazarus101 is right, the chipset is the S3C6410. An early rumour probably had it as Snapdragon and that got spread around. In fairness to PDADB, they do have it marked as "Preliminary specifications".
Even so, the Spica still looks to be better. The CPU cores of both are almost identical: The Galaxy's
ARM1136J(F)-S versus the Spica's
ARM1176JZ(F)-S (the Spica's one is slightly newer, just has a couple of feature extensions). Which means the clock speeds are directly comparable, so Spica's blows the Galaxy out of the water there. The Galaxy does have a 2nd core though, a much-lower spec and older 256MHz processor, so it will gain a performance boost through multi-tasking.
Who wins with the rest of the chipset features is up for debate. For anyone who's interested in reading more, the datasheet for the MSM7200A is
here (PDF), and the homepage for the S3C6410 is
here (there's some good PDFs near the bottom of the page under specification data).
Not sure who wins in the RAM stakes, I've seen multiple different figures from multiple different sources. Can't seem to find the info on my Spica either