Burner not making CDs well

[rjc7394]

I get scratching noises on CDs sometimes when I burn mp3s. It's usually towards the end of the CD. Some CD-RWs are OK. I've used memorex for 18 mths and they're great (best brand that's offered around here). I have a Samsung DVD-CD burner which is a little over a year old. I have three different burner softwares installed because they serve different purposes. The Ashampoo is lousy (sound level of mp3s drop) with mp3s but good with DVD-RW. Also Cheetah and Easy CD-DA Extractor which is versatile. I try to burn at low speeds (4x). I just bought Memorex Ultra-Speed CD-RW (24x). I had a few of them that didn't want to work at all after they were burned so I'm staying away from the fast CDs. Maybe my burner is going? I've had this happen for over a year.

[glc]

Samsung burners are not noted for being high quality.