one pass or two pass (which is better?)

[The Linguist]

So I'm my computer is rather old and slow at rendering video and I'm wondering if the process will speed up by changing to a single pass encoding option in premier pro rather than a 2 pass. Is there any reason I should avoid single pass?

basically I don't know what is different.

[jman98]

Multipass encoders use the first pass to generate statistics about the video to improve quality in the next pass, so you should expect the quality to be better with 2 passes than 1 pass. Yes, 1 pass encoding is quicker, but you are trading quick encode time for lesser video quality.

[guns1inger]

If you don't need to hit a certain file size then you can do single pass quality based encoding instead. The quality should be as high as 2 pass VBR, but you can't choose the file size you will get.