Here's a small yet interesting addition... credit goes to Izumi. for informing me about this:

The Famicom's CPU went thru 4 versions. RP2A03E thru RP2A03H (I think US & Europe NES systems only contained 'G' & 'H'?). What's most interesting is that 93-bit looped noise wasn't implenented on the 'E' version.

~:: Oh Takuto, my kawaii catgod of fate ::~