Is it happen to your drive?

I found a very interesting thing:

I insert a DVD-RW into the dist and get performance and got the speed supported: 8310, 5540 and 2770. Then I enable real-time streaming and set the speed (SET STREAMING)and begin the writing operation. After I set the drive with 2770 and run the writing operation, no matter what speed I try to set, like 5540 or 8310, the drive still keep with the speed of 2770.

Another interesting thing: I require my drive to read about 3G data on the disc, the average read speed cannot approaching what the drive supports. But if I do it for several times continously, the speed can be increased gradually approaching to the supported speed.

I just do it on Windows. Would you like to tell me why this happened and have you ever encountered this before ?