By RPM count, the approximately equivalent CAV speed ratio between BD:DVD:CD is 12:4:3. Unknown for HD-DVD.

To calculate the burning time, one has to do the following:

Data diameter ratios:

- 8cm CD×1.6
- 12 cm: ×2,4.

So the average burning speed can be calculated by this mathematical formula:

((([DiameterRatio]—1.0)/2)+1)×[CAVspeed]÷[DiameterRatio].

Example for ×48 CAV on an 120mm CD-R:

(2.4-1.0)+1=1.7.

1.7×(48/2.4)=1.7×20=34×.

## Time calculation.

So burning a CD-R at ×34 on average, on an 700MB/80min disc would mean burning 34 seconds worth CDDA on average.

80min/34=2,352 Minutes (co-incidence to 2352b sectors?).

2 minutes and (0.352×60=21.12 seconds). In theory, after spinning up.

So practically, one can consider up to three minutes needed for maximum speed burning.