Ok, I thought about it more. Both are wrong, but in a way that together it looks like the 4460.
The first report was wrong because the 4460 runs at 1.5Ghz. No reason to clock down its native speed, and the second report is sure of a 1.5GHz dual-core.
But the second report is wrong here:
According to our source, the device codenamed Nexus Prime is going to ship with Samsung's own chipset, with a blazingly fast dual-core processor clocked at 1.5GHz. But wait, there's more.
On that chipset will also reside a powerful dual-core GPU from Imagination.
There is no current or going forward Samsung Exynos chipset with a SGX GPU. Samsung is committed to making it so most of the work can be done in house (or with exclusive suppliers like Yamaha) and they have committed to the Mali GPU architecture. Mali is ARM's GPU so it is maybe the most "pure" GPU, and gives them a way to get away from a supplier they once shared with Apple (Imagination).
But TI is a big fan of SGX GPUs, so you put all the evidence together and it looks like it is the TI 4460.
This is better than everyone is making it out to be then. At 1.5GHz this will be the fastest phone around CPU-wise (as TI is pretty much clock-for-clock with Samsung on CPUs), and the SGX450 GPU is clocked at a pretty insane 384 MHz. That is almost twice as high as the Galaxy S1's GPU's speeds. Benchmarks will show it to be a competitor- maybe even nearing the Mali.
Overall if its the 4460 that is a great thing. On Android CPU clock matters this most and on that count this will be a monster.