Update 1:
Answer from NVIDIA:
Hey Hilbert,
As our chips become more advanced, we are implementing more complex clocking inside the chip. 430MHz is the primary clock speed of the chip and can be verified by fill rate tests.
We will work with Rivatuner to read the correct registers in order to report the right clock.
Hope this makes sense.
Now if you disect that answer (as vague as it honestly is) we can make note of the fact that NVIDIA uses "Primary" clock speed. Obviously, there's a secondary clockspeed running also. Very likely there are surely different clocks for different pipes.
If 430 remains the primary clock then why can Asus (check that here) advertise it as 470 ?
That would be somewhat misleading to you, the consumer as you think it's an uber Ultra version or something like that. They sincerely use this to advertise:
Engine Clock 470 MHz**
**NV clock(430MHz)+Geometric Delta clock(40MHz)
As it seems nobody can explain the 40 MHz differential properly, yet is is being used as marketing gimmick, consumers automatically assume it's 470 MHz where that's not 100% true.