Just use good media from quality brand. After month and month of burning, testing, i have wasted about 100 or 150 dvd. So the result was not an hardware problem but really a poor media quality problem. If you see all my post you can i have a lot of problems. Now i just use quality media (verbatim, ritek(under ritek brand), ty). So now i have only good result (g04 are best than g05 on 1620).
My best burning was with benq 16 +r media (phillips c16 @ 16x).
So dont by ritek or mcc that or not good brand. All the time there are crap. For example i have buy datawrite 8x +r media = just 2 good on 25.
This my opinion after 2 years of burning = just quality media.
P.S: you can buy crap media, but after dont come here to cry.