The ViperLair has its turn at MSI's 64MB Geforce4 Ti4200.

The 64 Mb version of Ti4200 uses 3.6ns memory, so using the same equation:
1000 nanoseconds/1 second x 1/3.6 nanoseconds = 277.7 Mhz
The speed is doubled, bringing the clock speed to 556 Mhz.
But wait - this ram is running at 513 Mhz. Why would MSI underclock their memory? The card is an Nvidia chip - it's meant to deal with 500 Mhz memory. By using the better RAM, they can run the RAM at a higher speed than the specs call for - higher than the 500 Mhz mark, without damaging the RAM by maxing out its memory clock.