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Don’t use Memorex DL media. Use Verbatim. It’s just better quality all around.
If you must try to give your media a better burn strategy [I’d personally just return them], you can use MCSE. (search the forum)
And the lower burning = better quality thing is a myth when you’re using GOOD media. [Lowering the speed may save you on bad media, but it still doesn’t make for a quality burn]. http://club.cdfreaks.com/f33/slow-write-speeds-modern-drives-modern-media-no-good-247643/ Write your DL media at 4x, 6x, or 8x, depending on what gives you the best results.