Ram Experts: Why don't we have TDR or QDR ram yet?

[James Mason]

If DDR's whole advantage over the previous ram tech was just it was "double the data rate" why haven't they tried making "triple data rate" or "quadruple data rate" RAM yet?

I know the MHZ speed increases with each generation of DDR, and it's definitely tripled or quadrupled since original DDR.

 

[maxwellmelon]

how many peaks are there in a single cycle of a sine wave (two) that's why its Double is it transfers at data at the two peeks.

triple or quadruple transfer points in a single sine wave would be possible but would require a lot more work to determine the correct timing as data would need to transfer the next bit of data not on just an easy to determine peak. its just not simple/reliable so they don't do it(remember the receiving devices decoder has to match the same timing of the sending device or it could possible read the data to late/early). FYI I hate timing charts between devices and checking for timing issues.

also thank AMD for allowing us to use DDR ram instead of RDRAM that intel was pushing at the time.