I don't know what you're referring to then. BOTH drives have device buffer (and speed) dropouts during normal burning operation, at each OPC point, as I already explained. If you noticed a strong difference between both drives, then you should explain better what you're experiencing, because from the limited info in your first post it looks to me like there's nothing wrong at all..!

The best thing to do would be to use the "create disc" feature of CDSpeed and post the resulting graph. Worth a thousand words.