Yes your CPU and Ram does effect the speeds of Movie decoding and then burning on Nero and well any other programs. As Decoding and recoding video is the most demanding task for a computer.
Ps. how much memory (i.e. cpu and ram do you have?) I have an old P3 2.8 gb and 1.5 gb DDR ram. This takes like 2 hours on average to make a Video DVD with menus and all (Note: I am using Nero 7 Ultra... upgrade for free )
Ps. Try setting your burn option into Low prioity during the decoding stage. This helps.
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