I have observed 2 things on my own computer when “burning” DVDRs:
Firstly: When the actual DVDR is “burning” and I am doing some other action that uses some CPU at the same time as the “burn”, the “quality” of the burn suffers and the “Transfer Rate” in Nero CD-DVD Speed shows this up.
Secondly: After I have “burn’t” a DVDR and I run it through the “Transfer Rate” in Nero CD-DVD Speed, if while the test is running I do again some action that uses CPU the actual results from the test come out “distorted”, ie if I run the test again and not do any other actions that use CPU the test results are different. I have run a test on a “burn’t” DVDR and used the computer for other things while the test was running and the results showed that it was a bad “burn”. Then when I have re-run the test and NOT used the computer the test results have showed that the burn was extremely good.
When my NEC 2500A is burning a full DVDR the actual CPU usage does not go over 10% and when it gets to 8X it is down below 5% usually, I have 1GB of ram as well, so I am not sure why the burn suffers when I run other actions during it or why the test results are distorted when I do something else while running the test.