Also depends on the quality of burner, if you are using some crappy laptop burner don't expect good quality burns. I burn at 4x all console games for PS2, XBOX, XBOX360 and never had a problem.
C2D E6750 @ 3.2Ghz, 4GB 800MHz DDR2 4-4-4-12, GeForce GTX 260 c216 OC 896MB, 3.2TB, Windows 7 Ultimate x64
Xbox 360 Elite, PS2 Slim, Xbox